U.S. patent application number 15/600922 was filed with the patent office on 2018-11-22 for heat exchanger.
The applicant listed for this patent is Daikin Applied Americas Inc.. Invention is credited to Louis A. Moreaux, Jeffrey Stamp, Michael Wilson.
Application Number | 20180335234 15/600922 |
Document ID | / |
Family ID | 62555137 |
Filed Date | 2018-11-22 |
United States Patent
Application |
20180335234 |
Kind Code |
A1 |
Stamp; Jeffrey ; et
al. |
November 22, 2018 |
HEAT EXCHANGER
Abstract
A heat exchanger includes a shell, a refrigerant distributor
disposed in the shell, and a heat transferring unit disposed in the
shell. The shell has a refrigerant inlet through which at least
liquid refrigerant flows and a shell refrigerant vapor outlet. The
refrigerant distributor includes a first portion and a second
portion. The first portion is connected to the refrigerant inlet to
receive refrigerant from the inlet. The first portion has at least
one first refrigerant liquid distribution opening and a first
refrigerant vapor distribution outlet opening. The second portion
is connected to the first portion to receive refrigerant from the
first refrigerant liquid distribution opening. The second portion
has at least one second refrigerant liquid distribution opening and
at least one second refrigerant vapor distribution outlet opening.
The heat transferring unit is disposed below the refrigerant
distributor to receive liquid refrigerant discharged from the
second portion of refrigerant distributor.
Inventors: |
Stamp; Jeffrey;
(Minneapolis, MN) ; Moreaux; Louis A.;
(Minneapolis, MN) ; Wilson; Michael; (Plymouth,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Daikin Applied Americas Inc. |
Minneapolis |
MN |
US |
|
|
Family ID: |
62555137 |
Appl. No.: |
15/600922 |
Filed: |
May 22, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 39/028 20130101;
F25B 39/00 20130101; F28D 7/163 20130101; F28F 2009/222 20130101;
F28F 9/0278 20130101; F25B 2400/23 20130101; F28F 9/0207 20130101;
F28D 2021/0071 20130101; F25B 2500/28 20130101; F25B 2339/0242
20130101; F28F 9/0273 20130101 |
International
Class: |
F25B 39/00 20060101
F25B039/00 |
Claims
1. A heat exchanger adapted to be used in a vapor compression
system, the heat exchanger comprising: a shell having a refrigerant
inlet that at least refrigerant with liquid refrigerant flows
therethrough and a shell refrigerant vapor outlet, with a
longitudinal center axis of the shell extending generally parallel
to a horizontal plane; a refrigerant distributor extending
longitudinally within the shell, the refrigerant distributor being
connected to the refrigerant inlet and including a first portion
connected to the refrigerant inlet to receive refrigerant from the
inlet, the first portion having at least one first refrigerant
liquid distribution opening and a first refrigerant vapor
distribution outlet opening, and a second portion connected to the
first portion to receive refrigerant from the at least one first
refrigerant liquid distribution opening, the second portion having
at least one second refrigerant liquid distribution opening and at
least one second refrigerant vapor distribution outlet opening, the
first refrigerant vapor distribution outlet opening communicating
with an interior of the shell so that refrigerant vapor exiting the
first refrigerant vapor distribution outlet opening enters the
interior of the shell outside of the refrigerant distributor
without passing into the second portion of the refrigerant
distributor, and the at least one second refrigerant vapor
distribution outlet opening communicating with the interior of the
shell so that refrigerant vapor exiting the at least one second
refrigerant vapor distribution outlet opening enters the interior
of the shell outside of the refrigerant distributor; and a heat
transferring unit disposed inside of the shell below the
refrigerant distributor to receive liquid refrigerant discharged
from the second portion of refrigerant distributor supplied to the
heat transferring unit.
2. The heat exchanger according to claim 1, wherein the shell
refrigerant vapor outlet is separate from the first and second
refrigerant vapor distribution outlet openings of the distributor
to distribute refrigerant vapor exiting the first and second
refrigerant vapor distribution outlet openings into the interior of
the shell before the refrigerant vapor flows out of the shell
refrigerant vapor outlet.
3. The heat exchanger according to claim 1, wherein the second
portion of the refrigerant distributor includes a pair of side
walls extending downwardly from the first portion of the
refrigerant distributor and a lateral wall extending between the
side walls to define at least one second distribution channel
together with the side walls.
4. The heat exchanger according to claim 3, wherein the at least
one second refrigerant vapor distribution outlet opening includes a
plurality of second refrigerant vapor distribution outlet openings
with at least one of the second refrigerant vapor distribution
openings formed in each of the side walls.
5. The heat exchanger according to claim 4, wherein the at least
one second refrigerant liquid distribution opening includes a
plurality of second refrigerant liquid distribution openings formed
in the lateral wall.
6. The heat exchanger according to claim 4, wherein each of the
side walls has a plurality of second refrigerant vapor distribution
outlet openings formed therein.
7. The heat exchanger according to claim 6, wherein the second
refrigerant vapor distribution outlet openings are longitudinally
extending slots disposed closer to upper ends of the side walls
than to lower ends of the side walls.
8. The heat exchanger according to claim 3, wherein the lateral
wall is divided into a pair of segments by a recess, with each
segment including a lateral section and an inner section extending
upwardly from the lateral section to divide the at least one second
distribution channel into a pair of second distribution channels,
the at least one second refrigerant liquid distribution opening
includes a plurality of second refrigerant liquid distribution
openings, and at least one of the second refrigerant liquid
distribution openings is formed in each of the lateral sections of
the distribution channels, and the at least one second refrigerant
vapor distribution outlet opening includes a plurality of second
refrigerant vapor distribution outlet openings, and at least one of
the second refrigerant vapor distribution openings is formed in
each of the side walls.
9. The heat exchanger according to claim 8, wherein each of the
side walls has a plurality of second refrigerant vapor distribution
outlet openings formed therein.
10. The heat exchanger according to claim 9, wherein the second
refrigerant vapor distribution outlet openings are longitudinally
extending slots disposed at upper ends of the side walls.
11. The heat exchanger according to claim 8, wherein the inner
sections are inclined relative to a vertical direction.
12. The heat exchanger according to claim 8, wherein upper ends of
the inner sections are connected to each other.
13. A heat exchanger adapted to be used in a vapor compression
system, the heat exchanger comprising: a shell having a refrigerant
inlet that at least refrigerant with liquid refrigerant flows
therethrough and a shell refrigerant vapor outlet, with a
longitudinal center axis of the shell extending generally parallel
to a horizontal plane; a refrigerant distributor extending
longitudinally within the shell, the refrigerant distributor being
connected to the refrigerant inlet and including a first portion
connected to the refrigerant inlet to receive refrigerant from the
inlet, the first portion having at least one first refrigerant
liquid distribution opening and a first refrigerant vapor
distribution outlet opening, and a second portion connected to the
first portion to receive refrigerant from the at least one first
refrigerant liquid distribution opening, the second portion having
at least one second refrigerant liquid distribution opening and at
least one second refrigerant vapor distribution outlet opening; and
a heat transferring unit disposed inside of the shell below the
refrigerant distributor to receive liquid refrigerant discharged
from the second portion of refrigerant distributor supplied to the
heat transferring unit, the second portion of the refrigerant
distributor including at least one longitudinally extending divider
plate arranged to divide the second portion into at least two
longitudinally extending duct sections, the at least one second
refrigerant liquid distribution opening being located on a first
side of the at least one divider plate to distribute liquid
refrigerant from one of the duct sections, and the at least one
first refrigerant liquid distribution opening being located to
distribute refrigerant into both of the duct sections of the second
portion.
14. The heat exchanger according to claim 1, wherein the
refrigerant distributor includes a shroud at least partially
overlying the first refrigerant vapor distribution outlet
opening.
15. The heat exchanger according to claim 14, wherein the shroud
has a top shroud plate and a pair of side shroud plates extending
downwardly from the top shroud plate to form a substantially
inverted U shaped configuration.
16. The heat exchanger according to claim 1, wherein the first
portion of the refrigerant distributor includes a first inner
distributor casing and a first outer distributor casing, the first
inner distributor casing is disposed within the first outer
distributor casing, the first inner distributor casing is connected
to the refrigerant inlet, and the first inner distributor casing
includes at least one first inner distribution opening to
distribute refrigerant into an interior space of the first outer
distributor casing, and the first outer distributor casing has the
at least one liquid refrigerant distribution opening and the
refrigerant vapor distribution outlet opening.
17. The heat exchanger according to claim 16, wherein the first
outer distributor casing includes a first tray part extending
longitudinally below the first inner distributor casing, and a
first canopy part extending longitudinally above the first inner
distributor casing, the first tray part and the first canopy part
are connected to each other on lateral sides of the first portion
of the refrigerant distributor, and the first canopy part has a
longitudinal length shorter than a longitudinal length of the first
tray part to form the first refrigerant vapor distribution outlet
opening.
18. The heat exchanger according to claim 17, wherein the first
tray part has the at least one first liquid refrigerant
distribution opening formed therein at a location below a vertical
location of the first refrigerant vapor distribution outlet
opening.
19. The heat exchanger according to claim 13, wherein the at least
one second refrigerant liquid distribution opening includes at
least one opening located on each side of the divider plate to
distribute liquid refrigerant from both of the duct sections.
20. The heat exchanger according to claim 19, wherein an amount of
liquid refrigerant distributed from the at least one second
refrigerant liquid distribution opening on opposite sides of the
divider plate is different.
21. The heat exchanger according to claim 13, wherein the divider
plate extends upwardly from a bottom internal surface of the second
portion of the refrigerant distributor.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] This invention generally relates to a heat exchanger adapted
to be used in a vapor compression system. More specifically, this
invention relates to a heat exchanger including a refrigerant
distributor.
Background Information
[0002] Vapor compression refrigeration has been the most commonly
used method for air-conditioning of large buildings or the like.
Conventional vapor compression refrigeration systems are typically
provided with an evaporator, which is a heat exchanger that allows
the refrigerant to evaporate from liquid to vapor while absorbing
heat from liquid to be cooled passing through the evaporator. One
type of evaporator includes a tube bundle having a plurality of
horizontally extending heat transfer tubes through which the liquid
to be cooled is circulated, and the tube bundle is housed inside a
cylindrical shell. There are several known methods for evaporating
the refrigerant in this type of evaporator. For example, there are
flooded evaporators, falling film evaporators, and hybrid falling
film evaporators.
[0003] Regardless of the type of evaporator, e.g., flooded, falling
film, or hybrid, a distributor is provided to distribute
refrigerant entering the evaporator to the tube bundle. U.S. patent
publication No. 2013/0277018 discloses one example of such a
distributor.
SUMMARY OF THE INVENTION
[0004] In at least a falling film evaporator it has been discovered
that it is desirable for as much as possible of the liquid
refrigerant be separated from the gas refrigerant in the
distributor so that only liquid refrigerant is distributed to the
tube bundle and only gas refrigerant exits the shell.
[0005] Therefore, one object of the present invention is to provide
an evaporator with a distributor that sufficiently separates liquid
and gas refrigerant.
[0006] It has been further discovered that if gas liquid separation
in the distributor is not sufficient, liquid droplets of
refrigerant can be contained in the gas refrigerant. Such liquid
droplets will not be distributed to the tube bundle and will exit
the evaporator with exit vapor flow and be returned to the
compressor. This phenomenon is called liquid carryover, which may
reduce performance of the evaporator and/or compressor, and thus,
the entire refrigerant cycle.
[0007] It has been further discovered that if gas liquid separation
in the distributor is not sufficient, gas bubbles can be contained
in the liquid refrigerant. Such gas bubbles can effectively reduce
the liquid amount supplied to the tube bundle, which may reduce
heat transfer performance of the evaporator.
[0008] Therefore, another object of the present invention is to
provide an evaporator with a distributor that distributes liquid
refrigerant to the tube bundle with reduced gas bubbles and reduces
liquid droplet content (liquid carryover) in refrigerant exit
vapor, and thus, improves performance of the evaporator and/or
compressor.
[0009] It has been further discovered that if vapor speed is
relatively high, vapor will entrain liquid. In addition, high vapor
speeds can cause excess shear on the liquid surface, impacting the
thickness (level) of liquid in the distributor. This varying liquid
level thickness in the distributor can lead to uneven dripping of
liquid (e.g., non-uniform distribution).
[0010] Therefore, another object of the present invention is to
provide an evaporator with a distributor that evenly distributes
liquid refrigerant.
[0011] It has also been discovered that insufficient gas liquid
separation can be more prevalent in a case where a Low Pressure
Refrigerant (LPR) refrigerant is used because a low pressure
refrigerant has a lower density.
[0012] Therefore, yet another object of the present invention is to
provide an evaporator with a distributor with improved liquid vapor
separation even when LPR refrigerant is used.
[0013] A heat exchanger according to a first aspect of the present
invention is adapted to be used in a vapor compression system. The
heat exchanger includes a shell, a refrigerant distributor, and a
heat transferring unit. The shell has a refrigerant inlet through
which at least refrigerant with liquid refrigerant flows and a
shell refrigerant vapor outlet. A longitudinal center axis of the
shell extends generally parallel to a horizontal plane. The
refrigerant distributor extends longitudinally within the shell and
is connected to the refrigerant inlet. The refrigerant distributor
includes a first portion and a second portion. The first portion is
connected to the refrigerant inlet to receive refrigerant from the
inlet. The first portion has at least one first refrigerant liquid
distribution opening and a first refrigerant vapor distribution
outlet opening. The second portion is connected to the first
portion to receive refrigerant from the at least one first
refrigerant liquid distribution opening. The second portion has at
least one second refrigerant liquid distribution opening and at
least one second refrigerant vapor distribution outlet opening. The
heat transferring unit is disposed inside of the shell below the
refrigerant distributor to receive liquid refrigerant discharged
from the second portion of refrigerant distributor supplied to the
heat transferring unit.
[0014] These and other objects, features, aspects and advantages of
the present invention will become apparent to those skilled in the
art from the following detailed description, which, taken in
conjunction with the annexed drawings, discloses preferred
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Referring now to the attached drawings which form a part of
this original disclosure:
[0016] FIG. 1 is a simplified, overall perspective view of a vapor
compression system including a heat exchanger according to a first
embodiment of the present invention;
[0017] FIG. 2 is a block diagram illustrating a refrigeration
circuit of the vapor compression system including the heat
exchanger according to the first embodiment of the present
invention;
[0018] FIG. 3 is a simplified perspective view of the heat
exchanger according to the first embodiment of the present
invention;
[0019] FIG. 4 is a simplified exploded perspective view of an
internal structure of the refrigerant distributor of the heat
exchanger illustrated in FIGS. 1-3;
[0020] FIG. 5 is a simplified partially exploded perspective view
of the internal structure of the refrigerant distributor of the
heat exchanger illustrated in FIGS. 1-4;
[0021] FIG. 6 is a simplified longitudinal cross sectional view of
the heat exchanger illustrated in FIGS. 1-3, as taken along section
line 6-6 in FIG. 3;
[0022] FIG. 7 is a simplified transverse cross sectional view of
the heat exchanger illustrated in FIGS. 1-3, as taken along section
line 7-7 in FIG. 3;
[0023] FIG. 8 is a further enlarged partial perspective view of an
inlet end of the distributor illustrated in FIGS. 4-7, along
section line 7-7 of FIG. 3;
[0024] FIG. 9 is a further enlarged partial perspective view of an
area spaced from the inlet end of the distributor illustrated in
FIGS. 4-7, along a middle section line 9-9 of FIG. 3 spaced from
the section line 7-7; and
[0025] FIG. 10 is a cross-sectional view of the distributor of FIG.
9, along middle section line 9-9 of FIG. 3 in order to illustrate
liquid/vapor heights and hole diameters.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Selected embodiments of the present invention will now be
explained with reference to the drawings. It will be apparent to
those skilled in the art from this disclosure that the following
descriptions of the embodiments of the present invention are
provided for illustration only and not for the purpose of limiting
the invention as defined by the appended claims and their
equivalents.
[0027] Referring initially to FIGS. 1 and 2, a vapor compression
system including a heat exchanger according to a first embodiment
will be explained. As seen in FIG. 1, the vapor compression system
according to the first embodiment is a chiller that may be used in
a heating, ventilation and air conditioning (HVAC) system for
air-conditioning of large buildings and the like. The vapor
compression system of the first embodiment is configured and
arranged to remove heat from liquid to be cooled (e.g., water,
ethylene glycol, brine, etc.) via a vapor-compression refrigeration
cycle.
[0028] As shown in FIGS. 1 and 2, the vapor compression system
includes the following four main components: an evaporator 1, a
compressor 2, a condenser 3, an expansion device 4, and a control
unit 5. The control unit 5 is operatively coupled to a drive
mechanism of the compressor 2 and the expansion device 4 to control
operation of the vapor compression system.
[0029] The evaporator 1 is a heat exchanger that removes heat from
the liquid to be cooled (in this example, water) passing through
the evaporator 1 to lower the temperature of the water as a
circulating refrigerant evaporates in the evaporator 1. The
refrigerant entering the evaporator 1 is typically in a two-phase
gas/liquid state. The refrigerant at least includes liquid
refrigerant. The liquid refrigerant evaporates as the vapor
refrigerant in the evaporator 1 while absorbing heat from the
water.
[0030] The vapor refrigerant is discharged from the evaporator 1
and enters the compressor 2 by suction. In the compressor 2, the
vapor refrigerant is compressed to the higher pressure, higher
temperature vapor. The compressor 2 may be any type of conventional
compressor, for example, centrifugal compressor, scroll compressor,
reciprocating compressor, screw compressor, etc.
[0031] Next, the high temperature, high pressure vapor refrigerant
enters the condenser 3, which is another heat exchanger that
removes heat from the vapor refrigerant causing it to condense from
a gas state to a liquid state. The condenser 3 may be an air-cooled
type, a water-cooled type, or any suitable type of condenser. The
heat raises the temperature of cooling water or air passing through
the condenser 3. Usually, hot water from the condenser is routed to
a cooling tower to reject the heat to the atmosphere. In addition,
optionally, the heated water (cooling water that cools the
refrigerant) can be used in a building as a hot water supply or to
heat the building.
[0032] The condensed liquid refrigerant then enters through the
expansion device 4 where the refrigerant undergoes an abrupt
reduction in pressure. The abrupt pressure reduction results in
partial expansion. The expansion device 4 may be as simple as an
orifice plate or as complicated as an electronic modulating thermal
expansion valve. Whether the expansion device 4 is connected to the
control unit will depend on whether a controllable expansion device
4 is utilized. The abrupt pressure reduction usually results in
partial expansion of the liquid refrigerant, and thus, the
refrigerant entering the evaporator 1 is usually in a two-phase
gas/liquid state at a relatively low temperature, low pressure.
[0033] Some examples of refrigerants used in the vapor compression
system are hydrofluorocarbon (HFC) based refrigerants, for example,
R410A, R407C, and R134a, hydrofluoro olefin (HFO), unsaturated HFC
based refrigerant, for example, R1234ze, and R1234yf, and natural
refrigerants, for example, R717 and R718. R1234ze, and R1234yf are
mid density refrigerants with densities similar to R134a. R450A and
R513A are mid pressure refrigerants that are also possible
refrigerants. A so-called Low Pressure Refrigerant (LPR) R1233zd is
also a suitable type of refrigerant. Low Pressure Refrigerant (LPR)
R1233zd is sometimes referred to as Low Density Refrigerant (LDR)
because R1233zd has a lower vapor density than the other
refrigerants mentioned above. R1233zd has a density lower than
R134a, R1234ze, and R1234yf, which are so-called mid density
refrigerants. The density being discussed here is vapor density not
liquid density because R1233zd has a slightly higher liquid density
than R134A. While the embodiment(s) disclosed herein are useful
with any type of refrigerant, the embodiment(s) disclosed herein
are particularly useful when used with LPR such as R1233zd. This is
because a LPR such as R1233zd has a relatively lower vapor density
than the other options, which leads to higher velocity vapor flow.
Higher velocity vapor flow in a conventional device used with LPR
such as R1233zd can lead to liquid carryover as mentioned in the
Summary above.
[0034] R1233zd is not flammable. R134a is also not flammable.
However, R1233zd has a global warming potential GWP<10. On the
Other hand, R134a has a GWP of approximately 1300. Refrigerants
R1234ze, and R1234yf are slightly flammable even though their GWP
is less than 10. Therefore, R1233zd is a desirable refrigerant due
to these characteristics, non-flammable and low GWP. While
individual refrigerants are mentioned above, it will be apparent to
those skilled in the art from this disclosure that a blended
refrigerant utilizing any two or more of the above refrigerants may
be used. For example, a blended refrigerant including only a
portion as R1233zd could be utilized.
[0035] It will be apparent to those skilled in the art from this
disclosure that conventional compressor, condenser and expansion
device may be used respectively as the compressor 2, the condenser
3 and the expansion device 4 in order to carry out the present
invention. In other words, the compressor 2, the condenser 3 and
the expansion device 4 are conventional components that are well
known in the art. Since the compressor 2, the condenser 3 and the
expansion device 4 are well known in the art, these structures will
not be discussed and/or illustrated in detail herein. In addition,
it will be apparent to those skilled in the art from this
disclosure that the vapor compression system may include a
plurality of evaporators 1, compressors 2, condensers 3 and/or
expansion devices 4. In other words, the illustrated embodiment
merely illustrates one relatively simple example of a vapor
compression system in accordance with the present invention.
[0036] Referring now to FIGS. 3-10, the detailed structure of the
evaporator 1, which is the heat exchanger according to the first
embodiment, will be explained. The evaporator I basically includes
a shell 10, a refrigerant distributor 20, and a heat transferring
unit 30. In the illustrated embodiment, the heat transferring unit
30 is a tube bundle. Thus, the heat transferring unit 30 will also
be referred to as the tube bundle 30 herein. However, it will be
apparent to those skilled in the art from this disclosure that
other structures for the heat transferring unit 30 may be used
without departing from the scope of the present invention.
Refrigerant enters the shell 10 and is supplied to the refrigerant
distributor 20. Then refrigerant distributor 20 performs gas liquid
separation and supplies the liquid refrigerant onto the tube bundle
30, as explained in more detail below. Vapor refrigerant will exit
the distributor 20 and flow into the interior of the shell 10, as
also explained in more detail below.
[0037] As best understood from FIGS. 3, 6 and 7, in the illustrated
embodiment, the shell 10 has a generally cylindrical shape with a
longitudinal center axis C (FIG. 6) extending generally in the
horizontal direction. Thus, the shell 10 extends generally parallel
to a horizontal plane P. The shell 10 includes a connection head
member 13 defining an inlet water chamber 13a and an outlet water
chamber 13b, and a return head member 14 defining a water chamber
14a. The connection head member 13 and the return head member 14
are fixedly coupled to longitudinal ends of a cylindrical body of
the shell 10. The inlet water chamber 13a and the outlet water
chamber 13b are partitioned by a water baffle 13c. The connection
head member 13 includes a water inlet pipe 15 through which water
enters the shell 10 and a water outlet pipe 16 through which the
water is discharged from the shell 10.
[0038] As shown in FIGS. 1-3 and 6, the shell 10 further includes a
refrigerant inlet 11a connected to a refrigerant inlet pipe 11b and
a shell refrigerant vapor outlet 12a connected to a refrigerant
outlet pipe 12b. The refrigerant inlet pipe 11b is fluidly
connected to the expansion device 4 to introduce the two-phase
refrigerant into the shell 10. The expansion device 4 may be
directly coupled at the refrigerant inlet pipe 11b. The liquid
component in the two-phase refrigerant boils and/or evaporates in
the evaporator 1 and goes through phase change from liquid to vapor
as it absorbs heat from the water passing through the tube bundle
30. The vapor refrigerant is drawn through the refrigerant outlet
pipe 12b to the compressor 2 by suction. The refrigerant that
enters the refrigerant inlet 11a includes at least liquid
refrigerant. Often the refrigerant entering the refrigerant inlet
11a is two-phase refrigerant. From the refrigerant inlet 11a the
refrigerant flows into the refrigerant distributor 20, which
distributes the liquid refrigerant over the tube bundle 30.
[0039] Referring now to FIGS. 4-9, the refrigerant distributor 20
will now be explained in more detail. The refrigerant distributor
20 is connected to the refrigerant inlet 11a and is disposed within
the shell 10. The refrigerant distributor 20 is configured and
arranged to serve as both a gas-liquid separator and a liquid
refrigerant distributor. The refrigerant distributor 20 extends
longitudinally within the shell 10 generally parallel to the
longitudinal center axis C of the shell 10. As best shown in FIGS.
4-5, the refrigerant distributor 20 includes an inlet channel part
21, a first tray part 22, a second tray part 23, a first canopy
part or first cover part 24, a second canopy part 25, and a shroud
26. A third tray part 27 is mounted below the second tray part 23,
and may be considered part of the distributor 20 or may be
considered a separate part from the distributor 20. The inlet
channel part 21, the first tray part 22, the second tray part, the
first canopy part 24 and the shroud 26 are rigidly connected
together as best understood from FIGS. 5-9. The third tray part 27
is disposed below the second tray part 23 in a slightly vertically
spaced arrangement.
[0040] As shown in FIG. 6, the inlet channel part 21 extends
generally parallel to the longitudinal center axis C of the shell
10 and the horizontal plane P. The inlet channel part 21 is fluidly
connected to the refrigerant inlet pipe 11b via the refrigerant
inlet 11a of the shell 10 so that the two-phase refrigerant is
introduced into the inlet channel part 21. The inlet channel part
21 has an inverted U-shaped rectangular cross-sectional
configuration. More specifically, the inlet channel part 21 has an
inverted U-shape with its laterally spaced free ends fixedly
connected to the first tray part 22. In the illustrated embodiment,
the first tray part 22 has a structure that mates with the inlet
channel part 21 to form part of tubular cross-sectional shape
together with the inlet channel part 21.
[0041] Referring again to FIGS. 4-9, the inlet channel part 21 is
fluidly connected to the refrigerant inlet pipe 11b via the
refrigerant inlet 11a so that the two-phase refrigerant is
introduced into the inlet channel part 21 from the refrigerant
inlet pipe 11b as mentioned above. The inlet channel part 21
preferably includes an inlet top part or wall (plate) 40 and a pair
of inlet lateral side parts or walls (plates) 42 and 44, as best
seen in FIG. 4. The inlet top plate 40 has a bushing B with hole
where the refrigerant inlet 11a is attached. The bushing B is
mounted in a hole of the top plate 40. The inlet lateral side
plates 42 and 44 extend downwardly from the inlet top plate 40 to
form an inverted U-shaped transverse cross-section. The inlet
lateral side plates 42 and 44 can be divided into first sections
without holes and second sections with holes 46. While individual
holes 46 are illustrated, the second sections can be perforated or
be formed of a mesh material. The inlet lateral side plates 42 and
44 are attached to the first tray part 22.
[0042] In the illustrated embodiment, the inlet top plate 40 and
the inlet side plates 42 and 44 are each formed of a rigid metal
sheet/plate material, which prevents liquid and gas refrigerant
from passing therethrough unless holes 46 or perforation is formed
therein. In addition, in the illustrated embodiment, the inlet top
plate 40 and the inlet side plates 42 and 44 are integrally formed
together as a one-piece unitary member. However, it will be
apparent to those skilled in the art from this disclosure that
these plates 40, 42 and 44 may be constructed as separate members,
which are attached to each other using any conventional technique
such as welding. In either case, the inlet plates 42 and 44 are
attached to the longitudinal center of the first tray part 22. In
addition, it will be apparent to those skilled in the art from this
disclosure that at least portions of each of the lateral side
plates 42 and 44 could be constructed at least partially of a metal
mesh material or any suitable perforated material so long as liquid
and gas communication therethrough is possible.
[0043] Referring again to FIGS. 4-9, the first tray part 22 will
now be explained in more detail. The first tray part 22 includes a
first bottom side part or wall (plate) 50, a pair of first lateral
side parts or walls (plates) 52 and 54, a pair of first end parts
or walls (plates) 56 and 58 and a channel section 60, as best seen
in FIG. 4. In the illustrated embodiment, the first lateral side
plates 52 and 54 extend upwardly from the first bottom plate 50 to
form a U-shape in transverse cross-section. The first end plates 56
and 58 are attached at opposite longitudinal ends of the first
bottom plate 50 and the first lateral side plates 52 and 54. The
channel section 60 is attached to a lateral center of the first
bottom plate 50. In the illustrated embodiment, each of the first
bottom plate 50, the pair of first lateral side plates 52 and 54,
the pair of first end plates 56 and 58 and the channel section 60
are constructed of metal sheet/plate material. In the illustrated
embodiment, the bottom plate 50 and the pair of lateral side plates
52 and 54 are integrally formed as a one-piece, unitary member. On
the other hand, in the illustrated embodiment, the end plates 56
and 58 are formed as separate members that are attached to the
longitudinal ends of the bottom plate 50 and the pair of lateral
side plates 52 and 54 by welding or any other suitable
technique.
[0044] The channel section 60 includes a planar part 62 attached to
the first bottom plate 50 and laterally spaced apart flange parts
64 and 66 extending upwardly from the planar part 62 to form a
trough therebetween, as best seen in FIG. 4. The trough and the
inlet channel part 21 are sized and shaped so that the inlet
channel part 21 is received in the trough between the flange parts
64 and 66 so that a rectangular cross-sectional shape is formed by
the inlet channel part 21 and the first bottom plate 50. The inlet
channel part 21 is preferably fixedly attached to the planar part
62. In the illustrated embodiment, each of the flange parts 64 and
66 is disposed where the refrigerant inlet 11a is disposed to
provide support and because no refrigerant flows out of the inlet
channel part 21 at this location. Optionally, additional flange
tabs that are smaller than the flanges 64 and 66 can be disposed in
a longitudinally spaced arrangement along the planar part 62 to be
useful in positioning the inlet channel part 21 during assembly,
without significantly impeding refrigerant flow out of the inlet
channel part 21 after assembly.
[0045] In the illustrated embodiment, the channel section 60 with
the flange parts 64 and 66 is a separate member from the bottom
plate 50. However, it will be apparent to those skilled in the art
from this disclosure that the flange parts 64 and 66 can be
integrally formed with the first bottom plate 50, or can be
separate flanges that are fixed to the first bottom plate 50 (e.g.,
by welding). In addition, it will be apparent to those skilled in
the art from this disclosure that the planar part 62 can be omitted
and the inlet channel part 21 can be directly attached to the first
bottom plate 50. In any case, channel section 60 (and/or the base
plate 50 where the channel section 21 is mounted) is preferably
free of openings in the planar part 62 thereof. The first base
plate 50 in a lateral center is also preferably free of openings.
Thus, regardless of whether the planar part 62 is provided,
refrigerant will have to flow out of the holes 46 of the inlet
channel part 21 and into the first tray part 22. On the other hand,
the areas of the first base plate 50 on opposite lateral sides of
the channel section 60 have holes 68 formed therein to pass liquid
refrigerant to the second tray part 23. More specifically, there
are a larger number of the holes 68 disposed inwardly of a smaller
number of the holes 68 to pass liquid to inner and outer areas of
the second tray part 23, as explained in more detail below. Even
more specifically, as best seen in FIG. 4 the larger number of
inward holes 68 extend the entire length of the distributor 20, and
the smaller number of the holes 68 are disposed only at the end of
the distributor 20 remote from the refrigerant inlet 11a, as
discussed in more detail below.
[0046] Preferably the end plates 56 and 58 are connected to the
base plate 50 and the lateral side plates 52 and 54 in a sealed
(i.e., air/liquid tight) manner. Likewise, the inlet channel part
21 is preferably attached to the channel section 60 and the end
plates 56 and 58 in a sealed (i.e., air/liquid tight) manner.
However, it will be apparent to those skilled in the art from this
disclosure that tight fitting connections with minor leakage from
the connection points or seams joining these parts may be
permissible as long as liquid and/or gas flow due to leakage does
not impact performance. One suitable technique for making such
connections is welding. Thus, refrigerant flowing into the
rectangular passage formed by the inlet channel part 21 and the
channel section 60 will remain therein except for when exiting from
the holes 46 formed in the lateral side plates 42 and 44.
[0047] Referring still to FIGS. 4-9, the first canopy part 24 will
now be explained in more detail. The first canopy part 24 is an
inverted U-shaped member formed of solid sheet/plate material. In
the illustrated embodiment, the first canopy part 24 is formed of
two sections welded together. In other words, a seam (not numbered)
is shown in the drawings. However, it will be apparent to those
skilled in the art from this disclosure that the first canopy part
24 could be formed of a single section. In the illustrated
embodiment, the first canopy part 24 includes a cover top part or
wall (plate) 70 and a pair of cover lateral side parts or walls
(plates) 72 and 74 extending downwardly from the cover top plate 70
to form an inverted U-shape in transverse cross-section. A width
between the pair of cover lateral side plates 72 and 74 is slightly
smaller than a width between the first lateral side plates 52 and
54 of the first tray part 22 so the first canopy part 24 can be
mounted in the first tray part 22.
[0048] In the illustrated embodiment, the pair of cover lateral
side plates 72 and 74 are integrally formed with the cover top
plate 70 (e.g., formed as a flat plate then bent downwardly). The
first canopy part 24 is attached to the first tray part 22 to
enclose the top thereof. Specifically, the cover top plate 70 is
attached to the first end plate 58. In addition, the pair of cover
lateral side plates 72 and 74 are attached to the first lateral
side plates 52 and 54, respectively. The pair of cover lateral side
plates 72 and 74 are also attached to the first end plate 58. More
specifically, because the width between the pair of cover lateral
side plates 72 and 74 is slightly smaller than a width between the
first lateral side plates 52 and 54 of the first tray part 22, the
cover lateral side plates 72 and 74 are attached in positions
laterally inside of the first lateral side plates 52 and 54.
[0049] The connections between these parts, like other connections
discussed above are preferably sealed (i.e., air/liquid tight)
connections. However, it will be apparent to those skilled in the
art from this disclosure that tight fitting connections with minor
leakage from the connection points or seams joining these parts may
be permissible as long as liquid and/or gas flow due to leakage
does not impact performance. One example of a suitable connection
is welding.
[0050] In the illustrated embodiment, the first canopy part 24
preferably has a longitudinal length as long as or longer than the
second inverted U-shaped section of the inlet channel part 21
having the holes 46. In addition, the first canopy part 24
preferably has a lateral width slightly narrower than a lateral
width of the first tray part 22, and a height at least as tall as
the lateral side walls of the first tray part 22. Furthermore, the
first canopy part 24 preferably has a height taller than a height
of the inlet channel part 21 to form a gas passage thereunder. When
the first canopy part 24 is attached to the first tray part 22, a
rectangular enclosed chamber is formed that extends from the first
end plate 58 to a spaced end of the first canopy part 24. The
spaced end of the first canopy part 24 is attached to the shroud 26
as explained below in more detail. The area of the distributor 20
extending from the spaced end of the first canopy part 24 (where
the shroud is attached) to the first end plate 58 that is above the
first tray part 22 and the inlet channel part 21 adjacent the
refrigerant inlet 11a forms a first refrigerant vapor distribution
outlet O. The holes 68 distribute liquid refrigerant into the
second tray part 23. The first refrigerant vapor distribution
outlet O distributes gas refrigerant into an interior of the shell
10 before the gas refrigerant exits through the shell vapor outlet
12a. This gas/liquid refrigerant separation/distribution is a first
stage of gas/liquid separation/distribution carried out by the
distributor 20.
[0051] Referring still to FIGS. 4-9, the second tray part 23 will
now be explained. The second tray part 23 is attached to a bottom
of the first tray part 22 and receives liquid refrigerant from the
holes 68. The second tray part 23 basically includes a bottom
lateral part or wall (plate) 90, a pair of lateral side parts or
walls (plates) 92 and 94 extending upwardly from the bottom lateral
wall 90, and end parts or walls (plates) 96 and 98 attached to
opposite longitudinal ends of the lateral wall 90 and opposite
longitudinal ends of the lateral side walls plates 92 and 94. The
second tray part 23 has a generally U-Shaped configuration, except
a recess R projects upwardly. Due to this arrangement of the recess
R, the bottom lateral wall (plate) 90 and the lateral side walls
(plates) 92 and 94 together form a substantially W-shaped
cross-sectional shape as best seen in FIGS. 7-9.
[0052] In addition, a pair of vertical divider plates 33 are
mounted on opposite sides of the recess R to divide the troughs on
opposite sides of the recess R. The vertical plates 33 are separate
members constructed of rigid sheet/plate material such as metal
(e.g. the same material as the second tray part 23) that are fixed
to the bottom lateral part 90 by welding or any suitable technique.
The divider plates 33 have heights approximately 3/4 of the height
of the second tray part 23. The smaller number of the holes 68 in
the first tray part 22 are located to feed liquid to the outer
sides of the divider plates 33 while the larger number of the holes
68 are located to feed liquid to the inner sides of the divider
plates 33, as best understood from FIGS. 4 and 10. The divider
plates 33 separate each of the troughs of the second tray part 23
into inner and outer duct sections. The inner duct sections are
closer to the recess R than the outer duct sections. However, these
inner and outer duct sections communicate at the shroud end of the
distributor 20, as best understood from FIGS. 4-5. Thus, the larger
number of inward holes 68 are located to feed refrigerant to the
inner duct sections of the second tray part 23, and the smaller
number of the outward holes 68 are located to feed refrigerant to
the outer duct sections of the second tray part 23 only at the end
of the distributor 20 remote from the refrigerant inlet 11a.
[0053] In the illustrated embodiment, the bottom lateral wall
(plate) 90 and the lateral side walls (plates) 92 and 94 are
integrally formed with each other as a one-piece unitary plate
member (e.g., as a flat plate that is then bent into the
illustrated shape). On the other hand, the end plates 96 and 98 are
separate members that are attached to opposite longitudinal ends of
the bottom lateral wall (plate) 90 and the lateral side walls
(plates) 92 and 94. However, it will be apparent to those skilled
in the art from this disclosure that the lateral side plates 92 and
94 could be formed separately from the bottom lateral plate and/or
the end plates 96 and 98 could be formed integrally. In any event,
the connections between these parts, like other connections
discussed above are preferably sealed (i.e., air/liquid tight)
connections. However, it will be apparent to those skilled in the
art from this disclosure that tight fitting connections with minor
leakage from the connection points or seams joining these parts may
be permissible as long as liquid and/or gas flow due to leakage
does not impact performance. One example of a suitable connection
is welding.
[0054] The second tray part 23 has a perimeter size slightly larger
than a perimeter size of the first tray part 22. Thus, the second
tray part 23 can partially vertically overlap with the first tray
part 22 and be attached to exterior face(s) of the first tray part
22. More specifically, in the illustrated embodiment, the pair of
lateral side walls (plates) 92 and 94 are attached to the pair of
first lateral side plates 52 and 54, respectively, using a
plurality of longitudinally arranged fasteners F as best understood
from FIGS. 4-5. The fasteners can be any suitable fasteners such as
screws, bolts, rives etc. Alternatively, it will be apparent to
those skilled in the art from this disclosure that the second tray
part 23 could be attached to the first tray part 22 using welding
or any other suitable joining technique. Preferably, the first and
second tray parts 22 and 23 are attached in an air/liquid tight
manner or at least a tight fitting manner such that minimal
vapor/liquid passes between the parts, like the other connections
discussed above.
[0055] Referring still to FIGS. 4-9, the bottom lateral wall 90
includes a recessed section 100, a pair of lateral sections 102a
and 104a, and a pair of inner sections 102b and 104b. The lateral
sections 102a and 104a extend toward each other from the side walls
92 and 94, respectively. The inner sections 102b and 104b extend
upwardly from the lateral sections 102a and 104a to the recessed
section 100. In the illustrated embodiment, the inner sections 102b
and 104b are inclined relative to the horizontal plane P and
inclined relative to a vertical direction V (FIG. 7) perpendicular
to the horizontal plane P (FIGS. 8-10). The recessed section 100
contacts an underside of the first tray part 22 (i.e., a bottom
surface of the base plate 50). Thus, the recessed section 100
serves to vertically position the second tray part 23 relative to
the first tray part 22.
[0056] The recessed section 100 can be attached to the base plate
50 or may merely contact the base plate 50. In either case, the
recess R (recessed section 100) divides the lateral wall 90 into a
pair of segments, with each segment including a lateral section
102a or 104a and an inner section 102b or 104b extending upwardly
from the lateral section 102a or 104a. In addition, the recess R
(recessed section 100) divides an interior space of the second tray
part at or below the recessed section 100 into a pair of second
distribution channels CH1 and/or CH2. The lateral sections 102a or
104a each have a plurality of holes 108 formed therein that are
second refrigerant liquid distribution openings. Thus, at least one
of the second refrigerant liquid distribution openings 108 is
formed in each of the lateral sections 102a or 104a of the
distribution channels CH1 and/or CH2. Upper ends of the inner
sections 102b and 104b are connected to each other by the recessed
section 100. In the illustrated embodiment, the holes 108 are only
located inward of the divider plates 33 adjacent the recess R. Thus
refrigerant received in the second tray part 23 outward of the
divider plates 33 need to flow around the divider plates 33 to the
holes 108. Momentum of the liquid may carry more liquid to the back
of the distributor than desired. The outer set of holes 68 on the
outward side can collect and drain this liquid into the outer ducts
of the second tray part 23, which can form outer "bleed off lines"
formed by the divider plate 33 to the drain holes that are not
separated using the divider plates 33.
[0057] Each of the sidewalls 92 and 94 includes a plurality of
second vapor distribution outlet openings 92a and 94a,
respectively, formed therein. In the illustrated embodiment, the
second vapor distribution outlet openings 92a and 94a are
positioned slightly below the recessed section 100 so as to be
position slightly below the base plate 50 at upper ends of the
distribution channels CHI and/or CH2. Thus, the shell refrigerant
vapor outlet 12a is separate from the first and second refrigerant
vapor distribution outlet openings O, 92a and 94a of the
distributor 20 to distribute refrigerant vapor exiting the first
and second refrigerant vapor distribution outlet openings O, 92a
and 94a into an interior of the shell before the refrigerant vapor
flows out of the shell refrigerant vapor outlet 12a. The second
refrigerant vapor distribution outlet openings 92a and 94a are
longitudinally extending slots disposed at upper ends of the side
walls 92 and 94, respectively.
[0058] Referring to FIGS. 4-8, the second canopy member 25 includes
a pair of laterally spaced canopy plates 35 and 37. In the
illustrated embodiment, each canopy plate has a zig-zag
configuration so as to be attached to the second tray part 23 and
to fit over the third tray part 27 in a mating arrangement.
However, it will be apparent to those skilled in the art from this
disclosure that other shapes may be used. The second canopy part 25
serves to prevent high speed vapor from entraining liquid from the
third tray part 27 and bring such liquid out into the interior of
the shell 10 on the outside of the distributor 20. Each of the
canopy plates 35 and 37 is are constructed of metal sheet/plate
material such as metal. In the illustrated embodiment, each of the
canopy plates 35 and 37 is attached to an outer side of the second
tray part 23 by welding or any other suitable technique. Thus, the
canopy plates 35 and 37 (the second canopy member 25) can be
considered part of the second tray part 23 or can be considered a
separate part. The canopy plates 35 and 37 extend along the entire
length of the distributor 20.
[0059] Referring still to FIGS. 4-8, the shroud 26 at least
partially overlies the first refrigerant vapor distribution outlet
opening O. In particular, the shroud 26 overlies the top of the
first refrigerant vapor distribution outlet opening O to divide the
opening O into two laterally spaced section (unnumbered). The
shroud 26 has a shroud top plate 80 and a pair of side shroud
plates 82 and 84 extending downwardly from the top shroud plate 80
to form a substantially inverted U shaped configuration. In
addition, the shroud 26 preferably includes end plates 88 on an end
of the shroud top plate 80 attached to the canopy member 24. The
shroud 26 is attached to the first tray part 22 and the first
canopy part 24 by attaching the shroud top plate 80 to the first
end plate 56 and the spaced end of the first canopy part 24 using
any suitable attachment technique. Welding is one example of a
suitable attachment technique.
[0060] Each shroud side plate 82 and 84 includes an inclined
section 82a and 84a extending from the shroud top plate 80, and
V-shaped tab members 82b and 84b extend upwardly and inwardly from
lower ends of vertical section 82b and 84b to form V-channels at
bottom ends thereof, respectively. Due to this configuration of the
shroud 26, refrigerant vapor will not flow vertically up out of the
first refrigerant vapor distribution outlet opening O, but will
have to flow either laterally sideways and/or downwardly out of the
first refrigerant vapor distribution outlet opening O before
flowing to the shell vapor outlet 12a. When doing visualization it
was seen that whey carry over occurs, high speed liquid collides
into the inclined sections 82a and 84a. However, the V-shaped tab
members 82b and 84b collect any of these droplets and drain them to
the end of the shroud 26.
[0061] The elements of the shroud 26 are preferably constructed of
rigid sheet/plate material such as sheet metal. The shroud top
plate 80 and the pair of side shroud plates 82 and 84 can be
constructed as a single member that is bent into the shape
illustrated herein. However, in the illustrated embodiment, the end
plates 88 are preferably constructed as separate members that are
attached to the shroud top plate 80 and the pair of side shroud
plates 82 and 84 using any suitable conventional technique such as
welding. In addition, in the illustrated embodiment, V-shaped tab
members 82b and 84b are constructed as separate members that are
attached to the pair of side shroud plates 82 and 84 using any
suitable conventional technique such as bolting (FIG. 8) or welding
(remaining FIGS). In addition, the shroud 26 in the illustrated
embodiment is welded to the parts of the distributor 20 along the
intersections (e.g., seams) in a tight fitting and/or air/liquid
tight arrangement like the other connections of the distributor 20
described above. The shroud 26 may assist in limiting liquid
carryover to the shell vapor refrigerant outlet 12a.
[0062] As best shown in FIGS. 4-8, the third tray part 27 will now
be explained in more detail. The third tray part 27 includes three
identical tray sections 27a that are aligned side-by-side along the
longitudinal center axis C of the shell 10. As shown in FIG. 5, an
overall longitudinal length of the three third tray parts 27a is
substantially the same as or slightly larger than a longitudinal
length of the second tray part 23 as shown in FIG. 5. Thus,
refrigerant dripping from the second tray part 23 will fall into
the third tray part 27. A transverse width of the third tray part
27 is set to be larger than a transverse width of the second tray
part 23 so that the third tray part 27 extends over substantially
an entire width of the tube bundle 30 as shown in FIG. 7. As shown
in FIGS. 5-6, each of the third tray parts 27a has a plurality of
third discharge apertures 28 from which the liquid refrigerant is
discharged downwardly toward the tube bundle 30. Thus, the
refrigerant distributor 20 can be considered to have at least one
third liquid refrigerant distribution opening 28 if the third tray
part 27 is considered part of the distributor 20 to distribute
liquid refrigerant. The third tray part 27 is preferably supported
by the heat transferring unit 30, as explained below.
[0063] Referring again to FIGS. 3-9, the combination of and
cooperation between the parts of the distributor 20 will now be
discussed in more detail. In the illustrated embodiment, the inlet
channel part 21, the first tray part 22, and the first canopy part
24 preferably form parts of a first portion D1 of the refrigerant
distributor 20 connected to the refrigerant inlet 11a to receive
refrigerant from the inlet 11a, with the first portion D1 having at
least one first refrigerant liquid distribution opening 68 and a
first refrigerant vapor distribution outlet opening O. Optionally,
the shroud 26 may also be considered part of the first portion D1
of the distributor 20. The second tray part 23 along with a bottom
of the first tray part 22 form parts a second portion D2 of the
distributor 20. The first portion D1 of the distributor 20 performs
gas/liquid refrigerant separation/distribution as a first stage of
gas/liquid separation/distribution carried out by the distributor
20. The second portion D2 of the distributor 20 performs gas/liquid
refrigerant separation/distribution as a second stage of gas/liquid
separation/distribution carried out by the distributor 20. The
third tray part 27 can be considered a third portion of the
refrigerant distributor 20, which serves to merely equally
distribute liquid refrigerant (does not perform gas/liquid
separation) received from the second portion D2 of the refrigerant
distributor 20 over the entire tube bundle 30.
[0064] The first portion D1 of the refrigerant distributor 20
includes a first inner distributor casing (formed by the inlet
channel part 21 and the channel section 60) and a first outer
distributor casing (formed by the first tray part 22, the first
canopy member 24 and optionally the shroud 26). The first inner
distributor casing is disposed within the first outer distributor
casing. The first inner distributor casing is connected to the
refrigerant inlet 11a, and the first inner distributor casing
includes at least one first inner distribution opening 46 to
distribute refrigerant into an interior space of the first outer
distributor casing. The first outer distributor casing has the at
least one liquid refrigerant distribution opening 68 and the
refrigerant vapor distribution outlet opening O. Therefore, the
first outer distributor casing includes the first tray part 22
extending longitudinally below the first inner distributor casing
(formed by the inlet channel part 21 and the channel section 60),
and the first canopy part 24 extending longitudinally above the
first inner distributor casing. The first tray part 22 and the
first canopy part 24 are connected to each other on lateral sides
of the first portion D1 of the refrigerant distributor 24. The at
least one first liquid refrigerant distribution opening 68 is
formed at a location below a vertical location of the first
refrigerant vapor distribution outlet opening O.
[0065] Therefore, the distributor 20 is connected to the
refrigerant inlet 11a and includes the first portion D1 (the inlet
channel part 21 being part of the first portion) connected to the
refrigerant inlet 11a to receive refrigerant from the inlet 11, the
first portion D1 having at least one first refrigerant liquid
distribution opening 68 and a first refrigerant vapor distribution
outlet opening O. In addition, the distributor 20 includes the
second portion D2 (the second tray part 23) connected to the first
portion D1 (the first tray part 22, which forms part of the first
and second portions D1 and D2) to receive refrigerant from the at
least one first refrigerant liquid distribution opening 68, the
second portion D2 having at least one second refrigerant liquid
distribution opening 108 and at least one second refrigerant vapor
distribution outlet opening (92a and 94a). Even though a plurality
of openings 92a and a plurality of openings 94a are included in the
illustrated embodiment, it will be apparent to those skilled in the
art from this disclosure that fewer openings are possible. In any
case, the second portion D2 of the distributor 20 includes at least
one second refrigerant vapor distribution outlet opening. In
addition, even though a pair of channels CH1 and CH2 are shown, it
will be apparent to those skilled in the art from this disclosure
that a single channel could be provided. However, including the
recess R and the pair of channels CH1 and CH2, reduces the volume
in the second portion (second tray 23) of the refrigerant
distributor, which can reduce the amount of refrigerant needed.
[0066] In addition, the second portion D2 of the refrigerant
distributor 20 includes a pair of side walls 92 and 94 extending
downwardly from the first portion D1 of the refrigerant distributor
20 and a lateral wall 90 extending between the side walls 92 and 94
to define at least one second distribution channel CH1 and/or CH2
together with the side walls 92 and 94. The at least one second
refrigerant vapor distribution outlet opening 92a and 92b includes
a plurality of second refrigerant vapor distribution outlet
openings 92a and 94a with at least one of the second refrigerant
vapor distribution openings 92a formed in the side wall 92 and at
least one of the second refrigerant vapor distribution openings 94a
formed in the side wall 94. Even though in the illustrated
embodiment a plurality of second refrigerant liquid distribution
openings are formed in each lateral wall, it will be apparent to
those skilled in the art from this disclosure that fewer openings
or even a single opening can be sufficient. In the illustrated
embodiment, the second refrigerant vapor distribution outlet
openings 92a and 94a are longitudinally extending slots disposed
closer to upper ends of the side walls 92 and 94 than to lower ends
of the side walls 92 and 94, respectively.
[0067] Referring again to FIGS. 4-9, the heat transferring unit 30
(tube bundle) will now be explained in more detail. The tube bundle
30 is disposed below the refrigerant distributor 20 so that the
liquid refrigerant discharged from the refrigerant distributor 20
is supplied onto the tube bundle 30. The tube bundle 30 includes a
plurality of heat transfer tubes 31 that extend generally parallel
to the longitudinal center axis C of the shell 10 as shown in FIG.
6. The heat transfer tubes 31 are made of materials having high
thermal conductivity, such as metal. The heat transfer tubes 31 are
preferably provided with interior and exterior grooves to further
promote heat exchange between the refrigerant and the water flowing
inside the heat transfer tubes 31. Such heat transfer tubes
including the interior and exterior grooves are well known in the
art. For example, GEWA-B tubes by Wieland Copper Products, LLC may
be used as the heat transfer tubes 31 of this embodiment. As best
understood from FIGS. 6-7, the heat transfer tubes 31 are supported
by a plurality of vertically extending support plates 32, which are
fixedly coupled to the shell 10. The support plates 32 also support
the third tray part 27, which is fixedly attached to the support
plates 32.
[0068] In this embodiment, the tube bundle 30 is arranged to form a
two-pass system, in which the heat transfer tubes 31 are divided
into a supply line group disposed in a lower portion of the tube
bundle 30, and a return line group disposed in an upper portion of
the tube bundle 30. As shown in FIG. 6, inlet ends of the heat
transfer tubes 31 in the supply line group are fluidly connected to
the water inlet pipe 15 via the inlet water chamber 13a of the
connection head member 13 so that water entering the evaporator 1
is distributed into the heat transfer tubes 31 in the supply line
group. Outlet ends of the heat transfer tubes 31 in the supply line
group and inlet ends of the heat transfer tubes 31 of the return
line tubes are fluidly communicated with a water chamber 14a of the
return head member 14. Therefore, the water flowing inside the heat
transfer tubes 31 in the supply line group is discharged into the
water chamber 14a, and redistributed into the heat transfer tubes
31 in the return line group.
[0069] Outlet ends of the heat transfer tubes 31 in the return line
group are fluidly communicated with the water outlet pipe 16 via
the outlet water chamber 13b of the connection head member 13.
Thus, the water flowing inside the heat transfer tubes 31 in the
return line group exits the evaporator 1 through the water outlet
pipe 16. Although, in this embodiment, the evaporator 1 is arranged
to form a two-pass system in which the water goes in and out on the
same side of the evaporator 1, it will be apparent to those skilled
in the art from this disclosure that the other conventional system
such as a one-pass or three-pass system may be used. Moreover, in
the two-pass system, the return line group may be disposed below or
side-by-side with the supply line group instead of the arrangement
illustrated herein.
[0070] Referring now to FIGS. 6-14, more detailed discussion of
operation and a heat transfer mechanism of the evaporator 1
according to the illustrated embodiment will be explained. As
described above, the refrigerant in a two-phase state or at least
including liquid refrigerant is supplied through the refrigerant
inlet 11a to the inlet channel part 21 of the refrigerant
distributor 20 via the inlet pipe 11b. The flow of refrigerant in
the evaporator 1 is schematically illustrated in FIGS. 6-9 with
arrows, and the inlet pipe 11b is omitted for the sake of brevity.
The vapor component of the refrigerant supplied to the refrigerant
distributor 20 is separated from the liquid component in the first
tray part 22 (a first stage separation). The liquid component of
the two-phase refrigerant is accumulated in the first tray part 22
and the gas component flows toward the first the refrigerant vapor
distribution outlet O. The liquid refrigerant flows out of the
first refrigerant liquid distribution opening 68 and into the
second tray 23. This is a first stage of refrigerant gas/liquid
separation/distribution.
[0071] Then in the second tray part 23, liquid refrigerant is
discharged downwardly out of the second first refrigerant liquid
distribution opening 108. In addition, in the second tray part 23,
any remaining gas refrigerant can be discharged out of the second
vapor distribution outlet openings 92a and 94a. This is a second
stage of refrigerant gas/liquid separation/distribution. The exact
flow areas through the holes 68 and 108 can be determined based on
experimentation. After the liquid refrigerant is distributed to the
third tray part 27, the liquid refrigerant received in the third
tray part 27 can then be equally distributed to the tube bundle 30.
Thus, the heat transferring unit 30 is disposed inside of the shell
10 below the refrigerant distributor 20 to receive liquid
refrigerant discharged from the second portion (from the second
tray part 23, after passing through the third tray part 27) of
refrigerant distributor 20.
[0072] As best understood from FIG. 6 refrigerant vapor (gas)
cannot flow directly from the first tray part 22 to the shell
refrigerant vapor outlet 12a. Rather, the gas (or vapor)
refrigerant must flow back towards the refrigerant inlet 11a (to
the left), through the refrigerant vapor distribution outlet O, and
then flow toward the shell refrigerant vapor outlet 12a.
Alternatively, vapor can flow from the second vapor distribution
outlet openings 92a and 94a or from the tube bundle 30 itself
toward the shell refrigerant vapor outlet 12a. However, flow from
these points would occur after two stages of refrigerant gas/liquid
separation/distribution.
[0073] Referring again to FIG. 6, in the illustrated embodiment,
both inlet side plates 42 and 44 have holes 46 formed continuously
along their entire heights but only along a predetermined length
L.sub.perf shorter than a length L.sub.dis of the distributor 20 In
addition, the predetermined length L.sub.perf is preferably shorter
than the length of the first canopy part 24. The divider plates 33
have lengths approximately equal to the predetermined length
L.sub.perf. However, it will be apparent to those skilled in the
art from this disclosure that different patterns of holes can be
used, or even a metal mesh material or any suitable perforated
material can be used instead of the plate material with holes.
Moreover, is will be apparent that the predetermined length
L.sub.perf can be determined depending on the pattern of holes 46
and/or the amount of flow therethrough, e.g., if the inlet lateral
side plates 42 and 44 are perforated material or mesh material
instead of plates with holes 46 formed therein the predetermined
length L.sub.perf could be shorter than as illustrated herein. For
example, holes 46 can be provided only above a predetermined
height, or continuous flanges can be provided in the first tray
part 22 so that liquid refrigerant only exits the inlet channel
part 21 above a certain level. In the illustrated embodiment, the
length L.sub.dis of the distributor 20 minus the predetermined
length L.sub.perf equals a solid length L.sub.sol. The smaller
number of outer holes 68 of the first tray part 22 are formed along
the length L.sub.sol as seen in FIG. 4 at the end of the
distributor 20 remote from the refrigerant inlet 11a. Thus, the
second portion D2 of the refrigerant distributor 20 includes at
least one divider plate 33 arranged to divide the second portion D2
into at least two duct sections (e.g., two pairs in the illustrated
embodiment), the second refrigerant liquid distribution openings
108 are located on a first side of the at least one divider plate
33 to receive refrigerant from one of the duct sections, and the
first refrigerant liquid distribution openings 68 are located to
distribute refrigerant into both of the duct sections of the second
portion D2. In the illustrated embodiment, the inlet top plate 40
is rigidly attached to the refrigerant inlet 11a, and the inlet
channel part 21 is fixed to the first tray part 22. The first
canopy part 24 is attached to the first tray part 22 to overlie the
areas with holes 46 of the inlet lateral side plates 42 and 44, as
explained in more detail below.
[0074] As shown in FIG. 7, the tube bundle 30 of the illustrated
embodiment is hybrid tube bundle including a falling film region
and a flooded region. The heat transfer tubes 31 in the falling
film region are configured and arranged to perform falling film
evaporation of the liquid refrigerant. The columns of the heat
transfer tubes 31 are preferably disposed with respect to the third
discharge openings 28 of the third tray part 27 so that the liquid
refrigerant discharged from the third discharge openings 28 is
deposited onto an uppermost one of the heat transfer tubes 31 in
each of the columns.
[0075] The liquid refrigerant that did not evaporate in the falling
film region continues falling downwardly by force of gravity into
the flooded region. While a hybrid tube bundle is disclosed in the
illustrated embodiment, it will be apparent to those skilled in the
art from this disclosure that other tube bundle designs can be used
together with the distributor 20 in the evaporator 1 of the present
invention.
[0076] In this embodiment, a fluid conduit 8 is fluidly connected
to the flooded region within the shell 10. Specifically, the shell
10 includes a bottom outlet pipe 17 in fluid communication with the
conduit 8. A pump device (not shown) may be connected to the fluid
conduit 8 to return the fluid from the bottom of the shell 10 to
the compressor 2 or may be branched to the inlet pipe 11b to be
supplied back to the refrigerant distributor 20. The pump can be
selectively operated when the liquid accumulated in the flooded
region reaches a prescribed level to discharge the liquid therefrom
to outside of the evaporator 1. It will be apparent to those
skilled in the art from this disclosure that instead of the fluid
conduit 8, a fluid conduit 8' can be coupled to the flooded region
at a location spaced from the bottom most point of the flooded
region. Moreover, it will be apparent to those skilled in the art
from this disclosure that the pump device (not shown) could instead
be an ejector (not shown). Pumps and ejectors such as those
mentioned above are well known in the art and thus, will not be
explained or illustrated in further detail herein.
GENERAL INTERPRETATION OF TERMS
[0077] In understanding the scope of the present invention, the
term "comprising" and its derivatives, as used herein, are intended
to be open ended terms that specify the presence of the stated
features, elements, components, groups, integers, and/or steps, but
do not exclude the presence of other unstated features, elements,
components, groups, integers and/or steps. The foregoing also
applies to words having similar meanings such as the terms,
"including", "having" and their derivatives. Also, the terms
"part," "section," "portion," "member" or "element" when used in
the singular can have the dual meaning of a single part or a
plurality of parts. As used herein to describe the above
embodiments, the following directional terms "upper", "lower",
"above", "downward", "vertical", "horizontal", "below" and
"transverse" as well as any other similar directional terms refer
to those directions of an evaporator when a longitudinal center
axis thereof is oriented substantially horizontally as shown in
FIGS. 6 and 7. Accordingly, these terms, as utilized to describe
the present invention should be interpreted relative to an
evaporator as used in the normal operating position. Finally, terms
of degree such as "substantially", "about" and "approximately" as
used herein mean a reasonable amount of deviation of the modified
term such that the end result is not significantly changed.
[0078] While only selected embodiments have been chosen to
illustrate the present invention, it will be apparent to those
skilled in the art from this disclosure that various changes and
modifications can be made herein without departing from the scope
of the invention as defined in the appended claims. For example,
the size, shape, location or orientation of the various components
can be changed as needed and/or desired. Components that are shown
directly connected or contacting each other can have intermediate
structures disposed between them. The functions of one element can
be performed by two, and vice versa. The structures and functions
of one embodiment can be adopted in another embodiment. It is not
necessary for all advantages to be present in a particular
embodiment at the same time. Every feature which is unique from the
prior art, alone or in combination with other features, also should
be considered a separate description of further inventions by the
applicant, including the structural and/or functional concepts
embodied by such feature(s). Thus, the foregoing descriptions of
the embodiments according to the present invention are provided for
illustration only, and not for the purpose of limiting the
invention as defined by the appended claims and their
equivalents.
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