U.S. patent application number 11/279160 was filed with the patent office on 2007-10-11 for shell and tube evaporator.
This patent application is currently assigned to AAF-McQuary Inc.. Invention is credited to Wei Chen.
Application Number | 20070235173 11/279160 |
Document ID | / |
Family ID | 38573917 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070235173 |
Kind Code |
A1 |
Chen; Wei |
October 11, 2007 |
SHELL AND TUBE EVAPORATOR
Abstract
An evaporator for use in a refrigeration system, the evaporator
having a shell defining an interior volume enclosing a tube bundle
comprising a plurality of elongate tubes, a water inlet in fluid
communication with a first end of the of the tube bundle for
directing water to the first end of the tube bundle and a water
outlet in fluid communication with a second end of the tube bundle
for passing water received from the second end of the tube bundle
out from the interior volume, includes a plurality of fluid
deflectors in fluid communication with a refrigerant inlet for
promoting mixing of incoming refrigerant in various states and
distributing such mixed refrigerant generally evenly throughout the
interior volume. A method of forming an evaporator is further
included.
Inventors: |
Chen; Wei; (Staunton,
VA) |
Correspondence
Address: |
PATTERSON, THUENTE, SKAAR & CHRISTENSEN, P.A.
4800 IDS CENTER
80 SOUTH 8TH STREET
MINNEAPOLIS
MN
55402-2100
US
|
Assignee: |
AAF-McQuary Inc.
Minneapolis
MN
|
Family ID: |
38573917 |
Appl. No.: |
11/279160 |
Filed: |
April 10, 2006 |
Current U.S.
Class: |
165/159 ;
29/890.07; 62/515 |
Current CPC
Class: |
F28D 2021/0071 20130101;
F25B 2339/0242 20130101; F28D 7/16 20130101; F28F 9/0268 20130101;
F25B 39/02 20130101; F25B 41/00 20130101; Y10T 29/49396 20150115;
F28F 13/12 20130101 |
Class at
Publication: |
165/159 ;
029/890.07; 062/515 |
International
Class: |
F28F 9/22 20060101
F28F009/22; F25B 39/02 20060101 F25B039/02; B21D 51/18 20060101
B21D051/18 |
Claims
1. An evaporator for use in a refrigeration system, the evaporator
having a shell defining an interior volume enclosing a tube bundle
comprising a plurality of elongate tubes, a water inlet in fluid
communication with a first end of the tube bundle for directing
water to the first end of the tube bundle and a water outlet in
fluid communication with a second end of the tube bundle for
passing water received from the second end of the tube bundle out
from the interior volume, comprising: a plurality of fluid
deflectors in fluid communication with a first refrigerant inlet
for promoting mixing of incoming refrigerant in various states and
distributing such mixed refrigerant generally evenly throughout at
least a first portion of the interior volume.
2. The evaporator of claim 1, the fluid deflectors being a
plurality of vanes.
3. The evaporator of claim 2, the vanes being angled at selected
angles to deflect the incoming refrigerant both upward and downward
relative to an evaporator center line.
4. The evaporator of claim 2 a first vane being generally planar
and being disposed generally on an evaporator centerline in a
generally horizontal disposition.
5. The evaporator of claim 2, a first pair of vanes, each vane of
the pair being generally planar and being disposed generally at a
first selected angle with respect to an evaporator centerline.
6. The evaporator of claim 5, a second pair of vanes, each vane of
the pair being generally planar and being disposed generally at a
second selected angle with respect to an evaporator centerline.
7. The evaporator of claim 1, the plurality of fluid deflectors
being formed integral, unitary with an end plate.
8. The evaporator of claim 1, the plurality of fluid deflectors
being cast integral, unitary with an end plate.
9. The evaporator of claim 1, each of the plurality of fluid
deflectors being formed such that a side margin of each of the
fluid deflectors conforms to an interior margin of an end plate at
a selected angle of disposition of each of the respective fluid
deflectors.
10. The evaporator of claim 1, each of the plurality of fluid
deflectors being formed of at least one planar trapezoidal
shape.
11. The evaporator of claim 1, including a plurality of fluid
deflectors in fluid communication with a second refrigerant inlet
for promoting mixing of incoming refrigerant in various states and
distributing such mixed refrigerant generally evenly throughout a
second portion of the interior volume.
12. The evaporator of claim 1, a first plurality of fluid
deflectors being operably coupled to a first portion of an end
plate and a second plurality of fluid deflectors being operably
coupled to a second portion of the end plate to define two
independent refrigerant flows.
13. The evaporator of claim 1, the plurality of fluid deflectors
being operably coupled to a first portion of an end plate and a
second portion of the end plate being without fluid deflectors to
define two independent refrigerant flows.
14. A method of forming an evaporator for use in a refrigeration
system, the evaporator having a shell defining an interior volume
enclosing a tube bundle comprising a plurality of elongate tubes, a
water inlet in fluid communication with a first end of the tube
bundle for directing water to the first end of the tube bundle and
a water outlet in fluid communication with a second end of the tube
bundle for passing water received from the second end of the tube
bundle out from the interior volume, comprising: selectively
disposing a plurality of fluid deflectors in fluid communication
with a first refrigerant inlet for promoting mixing of incoming
refrigerant in various states and distributing such mixed
refrigerant generally evenly throughout at least a portion of the
interior volume.
15. The method of claim 14, including forming the fluid deflectors
of a plurality of vanes.
16. The method of claim 15, including angling the vanes at selected
angles to deflect the incoming refrigerant both upward and downward
relative to an evaporator center line.
17. The method of claim 15, including forming a first vane being
generally planar and disposing the vane generally on an evaporator
centerline in a generally horizontal disposition.
18. The method of claim 15, including forming a first pair of vanes
and forming each vane of the pair planar and disposing each vane of
the pair generally at a first selected angle with respect to an
evaporator centerline.
19. The method of claim 18, including forming a second pair of
vanes and forming each vane of the pair planar and disposing each
vane of the pair generally at a first selected angle with respect
to an evaporator centerline.
20. The method of claim 14, including forming the plurality of
fluid deflectors integral, unitary with an end plate.
21. The method of claim 14, including casting the plurality of
fluid deflectors integral, unitary with an end plate.
22. The method of claim 14, including forming each of the plurality
of fluid deflectors such that a side margin of each of the fluid
deflectors conforms to an interior margin of an end plate at a
selected angle of disposition of each of the respective fluid
deflectors.
23. The method of claim 14, including forming each of the plurality
of fluid deflectors of a planar trapezoidal shape.
24. The method of claim 14, including fluidly communicating a
plurality of fluid deflectors with a second refrigerant inlet for
promoting mixing of incoming refrigerant in various states and
distributing such mixed refrigerant generally evenly throughout a
second portion of the interior volume.
25. The method of claim 14, including operably coupling a first
plurality of fluid deflectors being to a first portion of an end
plate, operably coupling a second plurality of fluid deflectors to
a second portion of the end plate and thereby defining two
independent refrigerant flows.
26. The method of claim 14, including operably coupling a plurality
of fluid deflectors to a first portion of an end plate, forming a
second portion of the end plate being without fluid deflectors and
thereby defining two independent refrigerant flows.
Description
TECHNICAL FIELD
[0001] The present invention relates to refrigeration systems. More
particularly, the present invention relates to direct expansion
evaporators for use in refrigeration systems.
BACKGROUND OF THE INVENTION
[0002] Evaporators for use in refrigeration systems are well known.
There is a need to improve the efficiency of evaporators and to
achieve a cost advantage in the evaporator market.
[0003] A problem with existing evaporators is that a refrigerant
vapor tends to float in the evaporator while a liquid refrigerant
tends to sink to the bottom of the evaporator. Such distribution
results in a decreased efficiency of the evaporator. There is a
need then to better mix refrigerant in both the liquid and vapor
states in order to better distribute the refrigerant throughout the
evaporator in the mixed condition. Such enhanced distribution would
contribute to an increased efficiency of the evaporator.
SUMMARY OF THE INVENTION
[0004] The present invention substantially meets the aforementioned
needs of the industry. The present invention provides for a
relatively simple means of mixing the liquid and vapor refrigerant
for better distribution of the mixed refrigerant throughout the
evaporator. The present invention provides for refrigerant
deflectors, more preferably vanes, disposed proximate the
refrigerant inlet. The vanes are variably angled with respect to a
center line of the evaporator in order to direct refrigerant both
upward and downward as the refrigerant enters the evaporator.
[0005] The aforementioned vanes can be integrated within a
generally conical endplate of the evaporator. In order to minimize
cost, the vanes may be cast integrally with the endplate. A one
piece endplate that incorporates the vanes of the present invention
substantially reduces cost of incorporation of the present
invention within an evaporator.
[0006] The present invention is an evaporator for use in a
refrigeration system, the evaporator having a shell defining an
interior volume enclosing a tube bundle comprising a plurality of
elongate tubes, a water inlet in fluid communication with a first
end of the tube bundle for directing water to the first end of the
tube bundle, and flow through baffle plates for best heat transfer
and a water outlet in fluid communication with a second end of the
tube bundle for passing water received from the second end of the
tube bundle out from the interior volume, including a plurality of
fluid deflectors in fluid communication with a refrigerant inlet
for promoting mixing of incoming refrigerant in various states and
distributing such mixed refrigerant generally evenly throughout the
interior volume. The present invention is further a method of
forming an evaporator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of an evaporator incorporating
the present invention and depicting the tube bundle resident within
the evaporator.
[0008] FIG. 2 is a perspective view of the tube sheet plate.
[0009] FIG. 3 is a perspective view of the exterior of an
endplate.
[0010] FIG. 4 is a perspective view of the interior of the endplate
of FIG. 3, depicting the vanes of the present invention.
[0011] FIG. 5 is a side view of the endplate of FIG. 3 cut away to
depict the angled disposition of the vanes.
[0012] FIG. 6 is a perspective view of an evaporator having two
independent refrigerant flow paths flowing inside of the tubes of
the tube bundle.
[0013] FIG. 7 is an exterior perspective view of the inlet end
plate of the evaporator of FIG. 6.
[0014] FIG. 8 is an interior perspective view of the inlet end
plate of the evaporator of FIG. 6.
[0015] FIG. 9 is a perspective view of a two pass evaporator.
[0016] FIG. 10 is a perspective view of the inlet/outlet end plate
of the evaporator of FIG. 9.
DETAILED DESCRIPTION OF THE DRAWINGS
[0017] The shell and tube evaporator of the present invention is
shown generally at 10 in FIG. 1. Evaporator 10 includes a shell 12
enclosing a tube bundle 32. A tube sheet plate view of the
evaporator is depicted in FIG. 2.
[0018] The shell 12 is comprised of a cylindrical outer shell 14
that is preferably made of a metallic material. The shell 14 is
formed of a wall that defines an inner volume 16 in which the tube
bundle 32 is disposed and through which a volume of refrigerant
flows.
[0019] The shell 12 is generally disposed in a horizontal
disposition and accordingly, a pair of supports 18 is affixed to
the underside of the shell 12 for supporting the evaporator 10 on
an underlying surface.
[0020] The shell 12 further includes a pair of endplates 20, 22
that seal the cylindrical outer shell 14. Endplate 20 is a
refrigerant inlet plate and endplate 22 is a refrigerant outlet
plate.
[0021] A refrigerant inlet 28 is defined in the endplate 20 and a
refrigerant outlet 30 is defined in the endplate 22.
[0022] A water inlet 24 is affixed to the cylindrical outer shell
14 and a water outlet 26 is also affixed to the cylindrical outer
shell 14 spaced apart from the water inlet 24. Generally, the water
inlet 24 and the water outlet 26 are disposed proximate the
endplates 20, 22 respectively.
[0023] The water inlet 24 is in fluid communication with the tube
bundle 32 at a first end thereof The water outlet 26 is in fluid
communication with the fluid bundle 32 at a second spaced apart end
thereof The tube bundle 32 is made up of a plurality of tubes and
baffle plates used for heat transfer enhancement that extend
generally the full length of the inner volume 16 of the shell 12.
An exemplary tube 34 of the tube bundle 32 is included for clarity.
With the baffle plates, water will pass each baffle plate so that
the water will have cross flow outside of the tube bundle. The
baffle plate will cause the water flow to become turbulent
flow.
[0024] The refrigerant inlet endplate 20 is shown generally in
FIGS. 3-4. Endplate 20 is preferably formed of two joined together
cones, a first cone 40 and a second cone 42. The first cone 40 has
its origin lying on the longitudinal axis 43 of the evaporator 10.
The angle defined between the longitudinal axis 43 and the first
cone 40 is generally greater than the angle defined between the
longitudinal axis 43 and the second cone 42. It should be noted
that the second cone 42 also has its origin lying on the
longitudinal axis 43. The second cone 42 is truncated proximate its
origin and a flange 45 is provided for coupling to a refrigerant
inlet pipe. The refrigerant inlet 28 is defined interior to the
flange 45. It is understood that the endplate 20 could be other
shapes, which would affect the shapes of the vanes discussed below.
For example, the end plated 20 could be formed of a single
cone.
[0025] Referring to FIGS. 3 and 4, the vanes of the present
invention are depicted. In a preferred embodiment, there are five
vanes disposed within the endplate 20, a center vane 44, a first
vane set 46, and a second vane set 48. Preferably, each of the
vanes 44, 46, and 48 is formed of two joined trapezoids in a common
plane, a first trapezoid 50 and a second trapezoid 52. Generally,
the angled sides of the first trapezoid 50 of each of the vanes 44,
46, and 48 has a lesser included angle than the angled sides of the
second trapezoid 52. Generally, the angled sides 51 of the first
trapezoid 50 conform with the interior margin of the second cone 42
while the angled sides 53 of the second trapezoid 52 conforms with
the interior margin of the first cone 40.
[0026] The sides 51, 53 may be formed integral the respective cones
42, 40. A single trapezoid shape would suffice for the vanes 44,
46, and 48 for use with an end plate 20 that is formed of a single
cone, as noted above. In any event, the vanes 44, 46, and 48 should
be formed such that the side margins of each of the vanes 44, 46,
and 48 conform the interior margin of the end plated 20 at the
selected angle of disposition of the respective vanes 44, 46, and
48 relative to the centerline 43. This is discussed in greater
detail below.
[0027] As noted above, in a preferred embodiment, the vanes 44, 46,
and 48 are formed integral with the endplate 20. Preferably, such
formation is by a casting process.
[0028] As depicted in FIGS. 3 and 4, the center vane 44 lies
coincident with a generally horizontal plane defined through the
longitudinal axis 43. The plane is generally parallel with the
underlying surface on which the evaporator 10 is mounted. The first
vane set 46 lies at a first angle A relative to the longitudinal
axis 43. An upper vane of the first vane set 46 is angled upward at
the angle A to deflect incoming refrigerant upward and the second
vane of the first vane set 46 is angled downward at the angle A' to
deflect incoming refrigerant downward.
[0029] The second vane set 48 is also angled relative to the
longitudinal axis 43, but at an angle B, a greater angle than that
of the first vane set 46. The upper vane of the second vane set 48
is angled upward at the angle B to deflect refrigerant that is
incoming to the top most portion of the evaporator 10. The lower
vane of the second vane set 48 is angled downward at the angle B'
to deflect incoming refrigerant to the lower most portion of the
evaporator 10. In this manner, the vanes 44, 46, and 48 provide
mixture of the incoming refrigerant liquid and vapor and promote
even distribution of the incoming refrigerant mixture throughout
the evaporator 10.
[0030] A second embodiment of the evaporator 10 of the present
invention is depicted in FIGS. 5-7. The evaporator 10 of this
embodiment acts like two evaporator, in that the evaporator 10 has
two independent refrigerant flow paths A and B. A substantially
vertical plate 54 (a first end of which is depicted in FIG. 7) in
the shell head at the inlet separates the two refrigerant flow so
that they do not mix together. The refrigerant in the two portions
16a, 16b does not mix in the evaporator 10, but passes thru the
evaporator 10 independently.
[0031] Effectively then, the evaporator 10 is with two independent
refrigerant circuits. Refrigerant flow is as indicated by the
arrows. A first refrigerant flow flows in refrigerant inlet 28a,
through the portion 16a of the evaporator inner volume 16 and out
the refrigerant outlet 30a. A second refrigerant flow flows in
refrigerant inlet 28b, through the portion 16b of the evaporator
inner volume 16 and out the refrigerant outlet 30b, the plate 54
acting to separate the two refrigerant flows.
[0032] The embodiment includes two sets of side-by-side vanes,
variously designated by a and b in FIG. 7. Additionally there is a
third vane set 56a and 56b. As noted above, in a preferred
embodiment, the vanes 44a, 44b, 46a, 46b, 48a, 48b, 56a, and 56b
are formed integral with the endplate 20.
[0033] A third embodiment of the evaporator 10 of the present
invention is depicted in FIGS. 8 and 9. The evaporator 10 of this
embodiment acts like a double pass evaporator, in that the
evaporator 10 has two refrigerant flow paths A and B and the
refrigerant makes two passes through the evaporator 10. A
substantially vertical plate 54 (a first end of which is depicted
in FIG. 9) in the shell head at the inlet separates the two
refrigerant flow so that they do not mix together.
[0034] The refrigerant is a single flow in the two portions 16a,
16b and does not mix in the evaporator 10. The refrigerant flow A
in portion 16a is reversed by the endplate 22 (endplate 22 in this
embodiment has no refrigerant inlets or outlets) and becomes
refrigerant flow B in portion 16b. Effectively then, the evaporator
10 has two side-by-side refrigerant flow paths. Refrigerant flow is
as indicated by the arrows.
[0035] The refrigerant flows in refrigerant inlet 28, through the
portion 16a of the evaporator inner volume 16 as depicted by arrow
A, is reversed by the end plate 22 (endplate 22 notably has no
refrigerant inlet or outlet). The refrigerant flow then flows
oppositely as depicted by arrow B through the portion 16b of the
evaporator inner volume 16 and out the refrigerant outlet 30 in the
end plate 20, the plate 54, similar to the plate 54 described
above, acting to separate the two flows.
[0036] The embodiment includes a single set of vanes disposed in a
first portion 60 of the endplate 20, as depicted in FIG. 9.
Additionally there is a third vane set 56. As noted above, in a
preferred embodiment, the vanes 44, 46, 48, and 56 are preferably
formed integral with the endplate 20. There are no vanes in the
second portion 62 of the end plate 20, the second portion 62 being
fluidly coupled to the refrigerant outlet 30.
[0037] In operation of the first embodiment of the evaporator 10,
water flows in through the water inlet 24 and around the outside
surface of the tubes 34 of the tube bundle 32 and of baffle plates,
where used. As the water proceeds from the water inlet 24 to the
water outlet 26, the water is chilled by refrigerant. The
refrigerant enters the refrigerant inlet 28 and is dispersed by the
vanes 44, 46, and 48 throughout the evaporator 10. The refrigerant
flows through the interior flow channel defined in the respective
tubes 34 of the tube bundle 32, cooling the water and
simultaneously evaporating the refrigerant. Accordingly, almost all
of the refrigerant mixture changes from a liquid state to a vapor
state in the evaporator 10 and flows from the evaporator 10 through
the refrigerant outlet 30 in the vapor state.
[0038] The above disclosure is not intended as limiting. Those
skilled in the art will readily observe that numerous modifications
and alterations of the device may be made while retaining the
teachings of the invention. Accordingly, the above disclosure
should be construed as limited only by the restrictions of the
appended claims.
* * * * *