U.S. patent application number 13/743959 was filed with the patent office on 2014-07-17 for plate heat exchanger with tension ties.
This patent application is currently assigned to HAMILTON SUNDSTRAND CORPORATION. The applicant listed for this patent is HAMILTON SUNDSTRAND CORPORATION. Invention is credited to Michael R. Barone, Matthew William Miller, Richard Rusich.
Application Number | 20140196869 13/743959 |
Document ID | / |
Family ID | 49920278 |
Filed Date | 2014-07-17 |
United States Patent
Application |
20140196869 |
Kind Code |
A1 |
Rusich; Richard ; et
al. |
July 17, 2014 |
PLATE HEAT EXCHANGER WITH TENSION TIES
Abstract
A plate heat exchanger includes a stack of main plates having
ridges and troughs to direct first and second flows of fluids
through cavities between the main plates to exchange heat between
the fluids while maintaining the first and second flows of fluids
separate from each other. The plate heat exchanger includes a first
end plate stacked at one end of the stack of main plates and a
second end plate stacked at an opposite end of the main plates.
Tension ties mechanically connect to each of the first and second
end plates through the stack of main plates.
Inventors: |
Rusich; Richard; (Ellington,
CT) ; Barone; Michael R.; (Amston, CT) ;
Miller; Matthew William; (Enfield, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HAMILTON SUNDSTRAND CORPORATION |
Windsor Locks |
CT |
US |
|
|
Assignee: |
HAMILTON SUNDSTRAND
CORPORATION
Windsor Locks
CT
|
Family ID: |
49920278 |
Appl. No.: |
13/743959 |
Filed: |
January 17, 2013 |
Current U.S.
Class: |
165/104.14 |
Current CPC
Class: |
F28D 9/005 20130101;
F28F 3/005 20130101; F28F 2225/00 20130101; F28F 3/083 20130101;
F28F 2275/205 20130101 |
Class at
Publication: |
165/104.14 |
International
Class: |
F28F 3/00 20060101
F28F003/00 |
Claims
1. A plate heat exchanger, comprising: a stack of main plates
having ridges and troughs to direct first and second flows of
fluids through cavities between the main plates to exchange heat
between the fluids while maintaining the first and second flows of
fluids separate from each other; a first end plate stacked at one
end of the stack of main plates; a second end plate stacked at an
opposite end of the main plates; and tension ties mechanically
connected to each of the first and second end plates through the
stack of main plates.
2. The plate heat exchanger of claim 1, wherein the tension ties
extend through openings in the main plates, the openings in the
main plates being in fluid communication with the cavities between
the main plates, and a first tension tie among the tension ties
includes an opening configured to permit a flow of fluid from the
first tension tie into a channel formed by the openings in the main
plates.
3. The plate heat exchanger of claim 2, wherein the first tension
tie includes a first end connector configured to connect to the
first end plate, a second end connector configured to connect to
the second end plate and a center column extending between the
first end connector and the second end connector, the center column
having an outer diameter less than an inner diameter of the channel
formed by the openings in the main plates.
4. The plate heat exchanger of claim 1, wherein the tension ties
extend through openings in the stack of main plates, the openings
in the stack of main plates forming a first channel from the first
end plate to the second end plate, a first tension tie among the
tension ties extending through the first channel, the first tension
tie being a hollow tension tie having an outer diameter that is
substantially the same as an inner diameter of the first channel,
the first tension tie including openings configured to permit a
flow of fluid between the hollow tension tie and the cavities
between the main plates.
5. The plate heat exchanger of claim 1, wherein the tension ties
include bottom connectors to mechanically fix the tension ties to
the second end plate.
6. The plate heat exchanger of claim 5, wherein the tension ties
are configured to resist a pressure exerted in opposing directions
against the first and second end plates, respectively.
7. The plate heat exchanger of claim 1, further comprising: fluid
fittings, wherein the tension ties include receptacles to receive
the fluid fittings and openings to permit fluid to flow between the
fluid fittings and the stack of main plates.
8. The plate heat exchanger of claim 7, wherein each of the tension
ties includes a first connection end including the receptacle, the
first connection end configured connect to one of the fluid
fittings along an inner diameter surface and to connect to the
first end plate along an outer diameter surface opposite the inner
diameter surface.
9. The plate heat exchanger of claim 1, further comprising: fluid
fittings, wherein the tension ties include receptacles configured
to mechanically connect the tension ties to the fluid fittings, a
first fluid fitting among the fluid fittings includes a recess
around an outer diameter circumference of the first fluid fitting
adjacent to an inner diameter surface of a first tension tie among
the tension ties, and the outer diameter surface of the first fluid
fitting has a larger diameter on one side of the recess and a
smaller diameter on an opposite side of the recess.
10. The plate heat exchanger of claim 1, wherein the tension ties
include top connectors configured to mechanically connect the
tension ties to the first end plate and a recess around an outer
diameter circumference of the top connector adjacent to an inner
diameter surface of the first end plate, and the inner diameter
surface of the first end plate has a larger diameter on one side of
the recess and a smaller diameter on an opposite side of the
recess.
11. The plate heat exchanger of claim 1, wherein a first tension
tie among the tension ties has a first end connector configured to
connect to the first end plate, a second end connector configured
to connect to the second end plate and a center column extending
between the first end connector and the second end connector, the
center column having a width less than a width of the first end
connector, and the center column includes at least one opening to
permit fluid to flow between the stack of main plates and a channel
through the first end connector.
12. The plate heat exchanger of claim 11, wherein the at least one
opening extends a length of the center column.
13. The plate heat exchanger of claim 11, wherein the at least one
opening is a fluted opening extending a length of the center
column.
14. A plate heat exchanger comprising: a stack of main plates
having ridges and troughs to direct first and second flows of
fluids through cavities between the main plates to exchange heat
between the fluids while maintaining the first and second flows of
fluids separate from each other; a first end plate stacked at one
end of the stack of main plates; a second end plate stacked at an
opposite end of the main plates; and a tension tie mechanically
connected to the first end plate and the second end plate to resist
a pressure exerted against at least one of the first and second end
plates, the tension tie including a fluid fitting mount to receive
a fluid fitting.
15. The plate heat exchanger of claim 14, wherein the fluid fitting
mount includes a recess having an inner diameter configured to
receive a fluid fitting of a substantially same outer diameter, the
inner diameter of the recess being opposite an outer diameter of
the tension tie, the outer diameter of the tension tie configured
to connect to an inner diameter an opening in the first end
plate.
16. The plate heat exchanger of claim 15, wherein the tension tie
includes a brazing recess around the outer diameter opposite the
fluid port mount, the brazing recess located adjacent to the inner
diameter of the opening in the first end plate.
17. The plate heat exchanger of claim 16, wherein the inner
diameter of the opening in the first end plate includes a brazing
region on one side of the brazing recess and a pilot region on an
opposite side of the recess, the brazing region having an inner
diameter greater than an inner diameter of the pilot region.
18. The plate heat exchanger of claim 14, wherein the tension tie
includes at least one opening to permit fluid flow between a fluid
fitting in the fluid fitting mount and the stack of main plates.
Description
BACKGROUND OF THE INVENTION
[0001] Embodiments of the invention relate to a plate heat
exchanger, and in particular to a heat exchanger having tension
ties as ports.
[0002] Plate heat exchangers are widely used in the commercial
industry as a means of exchanging energy between two liquids. The
construction consists of a series of main plates having ribbed
patterns on their surfaces and stacked one on top of the other.
This arrangement forms channels between the plates through which
the two liquids pass. As the two liquids enter their respective
inlet ports they are independently directed to flow into
alternating fin channels which permits heat to transfer from one
liquid to the other. In order to maintain separation of the two
liquids within the ports, the main plates incorporate local
depressions in the port areas which alternately block off the flow
passage from the port to the fin channels. In this way each port is
hydraulically connected to every other fin channel. Each plate is
coated with a braze filler metal. The entire heat exchanger
assembly is placed in a furnace where the filler metal is melted
creating a metallurgical bonds between the plates and forming a
fluid seal.
[0003] Plate heat exchangers are subjected to stresses from
internal fluid pressures. Stress resides in the main plates as the
fluid pressure tries to separate each plate. The top plate and
bottom plate provide some additional support and stiffness to
resist the internal pressure. The load emanating from the fluid
pressure in the vicinity of the ports is commonly called a plug
load. The area immediately surrounding the port areas is inherently
subjected to high stresses due to the reduction of material to form
the port holes which must exist to allow fluid flow. However the
rectangular shape of the heat exchanger does not function as an
efficient pressure vessel. Material may be added to the top and
bottom plates to increase strength, but adding the material also
increases a weight of the plate heat exchanger.
[0004] The position tolerance of the ports is subject to the
ability to maintain a repeatable and consistent stack height of the
main plates. Small variations in the material thickness of the main
plates (in the order of micrometers) will multiply by the number of
main plates. An 80 plate heat exchanger, for example can differ in
stack height from unit to unit by 2.03 millimeters (mm) if each
main plate had a variation of just 0.00254 mm. When considering the
additional tolerance associated with other components of the heat
exchanger, the resultant position tolerance of the ports can be
2.54 mm, for example. This large variation from unit to unit is
unacceptable for installations where precision is critical, such as
in aerospace applications.
BRIEF DESCRIPTION OF THE INVENTION
[0005] Embodiments of the present invention include a plate heat
exchanger which includes a stack of main plates having ridges and
troughs to direct first and second flows of fluids through cavities
between the main plates to exchange heat between the fluids while
maintaining the first and second flows of fluids separate from each
other. The plate heat exchanger includes a first end plate stacked
at one end of the stack of main plates and a second end plate
stacked at an opposite end of the main plates. Tension ties
mechanically connect to each of the first and second end plates
through the stack of main plates.
[0006] Embodiments of the invention further include a plate heat
exchanger which includes a stack of main plates having ridges and
troughs to direct first and second flows of fluids through cavities
between the main plates to exchange heat between the fluids while
maintaining the first and second flows of fluids separate from each
other. The plate heat exchanger includes a first end plate stacked
at one end of the stack of main plates and a second end plate
stacked at an opposite end of the main plates. The plate heat
exchanger includes a tension tie mechanically connected to the
first end plate and the second end plate to resist a pressure
exerted against at least one of the first and second end plates,
the tension tie including a fluid fitting mount to receive a fluid
fitting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features, and advantages of the invention are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0008] FIG. 1 illustrates a lengthwise side view of a heat
exchanger according to one embodiment of the invention;
[0009] FIG. 2 illustrates a widthwise side view of a heat exchanger
according to one embodiment of the invention;
[0010] FIG. 3 is a cut-away view of a portion of a tension tie
according to one embodiment of the invention;
[0011] FIG. 4 is a tension tie according to one embodiment of the
invention;
[0012] FIG. 5 is a tension tie according to another embodiment;
[0013] FIG. 6 is a tension tie according to another embodiment;
and
[0014] FIG. 7 is a tension tie according to another embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Conventional plate heat exchangers are subject to stresses,
particularly around port openings in the end plates. Embodiments of
the invention relate to a plate heat exchanger having ports that
are tension ties to provide support at the ends of the plate heat
exchanger.
[0016] FIG. 1 illustrates a plate heat exchanger 100 according to
one embodiment. The plate heat exchanger 100 includes main plates
110 having ridged regions 111. The ridged regions 111 may have a
herringbone or chevron pattern to increase a surface area of the
main plate 110 contacted by the fluid and to generate turbulence in
the fluid. In FIG. 1, only three main plates 110a, 110b and 110c
are illustrated for purposes of description. However, in a complete
plate heat exchanger 100, the main plates 110 are stacked on top of
each other between the bottom end plate 130 and the top end plate
120. Openings are formed in the main plates 110 at locations on the
main plates 110 corresponding to the ports 150a and 150b. The main
plates 110 are provided, alternatingly, with protrusions or
recesses surrounding the openings to alternate a fluid that enters
a cavity between the main plates. For example, a first fluid may
enter first, third and fifth cavities between the main plates, and
a second fluid may enter second, fourth and sixth cavities. The
fluids are maintained separate and exchange heat as they flow
through the cavities.
[0017] The plate heat exchanger 100 includes a first end plate 120,
also referred to herein as a top end plate 120 for purposes of
description. The plate heat exchanger 100 also includes a second
end plate 130, also referred to herein as a bottom end plate 130
for purposes of description. The top end plate 120 and bottom end
plate 130 are positioned at opposite sides of the plurality of main
plates 110. It is understood that although the terms "top" and
"bottom" may be used for purposes of description, embodiments of
the invention encompass a plate heat exchanger 110 having the first
and second end plates 120 and 130 arranged with any spatial
alignment relative to an earth plane. While FIG. 1 illustrates only
one top end plate 120 and only one bottom end plate 130,
embodiments of the invention encompass plate heat exchangers having
seal plates and end plates instead of one integrated end plate at
each end of the heat exchanger.
[0018] The illustrated top end plate 120 includes openings to
receive the fluid fittings 150a and 150b, as well as two additional
fluid fittings not shown in FIG. 1. While particular shapes are
used in FIG. 1 to represent the main plates 110, end plates 120 and
130 and fittings 150a and 150b, it is understood that these and
other elements may have any desired shape. For example, the main
plates 110 may have substantially rectangular, square, oval or any
polygonal shape.
[0019] In embodiments of the present invention, tension ties 140
are mechanically connected to each of the top plate 120 and the
bottom plate 130. The fittings 150a and 150b are set directly into
the tension ties 140 rather than the top plate 120, such that
vibration or movement of the top plate 120 does not substantially
affect the stability of the fittings 150a and 150b. As the fluid
pressure exerts force against the top and bottom end plates 120 and
130, the tension ties 140 resist the load and keep the top and
bottom plates 120 and 130 together
[0020] While FIG. 1 illustrates a side lengthwise view of the plate
heat exchanger 100 having some main plates 110 omitted for clarity
in description, FIG. 2 illustrates a side widthwise cut-out view of
the plate heat exchanger 100. The heat exchanger 100 includes the
top end plate 120, bottom end plate 130 and main plates 110. In
FIG. 2, stacked main plates 110a and 110d are illustrated as being
stacked adjacent to the top end plate 120, stacked main plates 110c
and 110e are illustrated as being stacked adjacent to the bottom
end plate 130 and main plate 110b is illustrated as being located
along center columns 141a and 141b of tension ties 140a and 140b,
respectively. It is understood that the main plates 110a-110e are
merely representative examples of main plates 110 that are stacked
to span the entire distance between the top end plate 120 and the
bottom end plate 130. The main plates 110 include openings 112,
represented by the opening 112b in main plate 110b, to permit and
direct fluid flow between the plates 110.
[0021] The bottom end plate 130 includes fasteners 131a and 131b.
Each tension tie 140a and 140b includes first connectors 144a and
144b, which may also be referred to as bottom connectors 144a and
144b, to connect to the fasteners 131a and 131b. The tension ties
140a and 140b also include second connectors 143a and 143b, which
may also be referred to as top connectors 143a and 143b, and center
columns 141a and 141b that connect the bottom connectors 144a and
144b with the top connectors 143a and 143b. The tension ties 140a
and 140b include openings 142a and 142b that permit fluid flow into
and out from the stack of main plates 110.
[0022] The top connectors 143a and 143b are configured to receive
the fluid fittings 150a and 150c, such that an outer
circumferential surface 151a and 151c of the fluid fittings 150a
and 150c contacts an inner circumferential surface 145a and 145b of
the tension ties 140a and 140b. The fluid fittings 150a and 150c
also include conduits 152a and 152c to permit fluid flow from
outside the fluid fittings 150a and 150c into and out from the
stack of main plates 110.
[0023] In operation, the bottom connectors 144a and 144b of the
tension ties 140a and 140b are connected to the fasteners 131a and
131b to mechanically connect the tension ties 140a and 140b to the
bottom plate 130. The connection of the bottom connectors 144a and
144b to the fasteners 131a and 131b may be a screw or other
fastening mechanism, or may be merely a fitting of a slot onto a
protrusion, which may then be brazed or welded to form a permanent
connection. Main plates 110, including the illustrated example main
plates 110a-110e, are stacked between the bottom plate 130 and the
top plate 120. The top plate 120 is stacked on the top-most main
plate 110a. The fluid fittings 150a and 150c are inserted into the
top connectors 143a and 143b of the tension ties 140a and 140b. The
connections between the tension ties 140a and 140b and the bottom
plate 130, between the bottom plate 130 and the bottom-most main
plate 110c, between each of the main plates 110, between the
top-most main plate 110a and the top end plate 120, between the
tension ties 140a and 140b and the top end plate 120, and between
the tension ties 140a and 140b and the fluid fittings 150a and 150c
may be connected by brazing or by any other welding method or
adhesive method.
[0024] When fluid F is input into the fluid fitting 150a, the fluid
flows through the channel 152a, out of the openings 142a of the
tension tie 140a into the stack of main plates 110. Openings 112 in
the main plates 110 permit the fluid F to flow into some cavities
between main plates 110 while fluid flow is restricted from other
openings 112 to prevent fluid flow to some cavities between main
plates 110. Another fluid fitting (not shown) also allows fluid
flow in to the stack of main plates 110. The fluid flows may be
allowed into alternating cavities between main plates to facilitate
heat transfer between the fluids. The tension tie 140b includes
openings 142b to permit the fluid F to flow out from the stack of
main plates 110 into the channel 152c and out from the fluid
fitting 150c.
[0025] During operation, the fluids in the stack of main plates 110
generates pressure outward against the bottom end plate 130 and the
top end plate 120. The tension ties 140a and 140b resist the
pressure and maintain the top and bottom end plates 120 and 130 in
position. The tension ties 140a and 140b are connected directly to
the fluid fittings 150a and 150c, stabilizing the fluid fittings
150a and 150c.
[0026] In one embodiment, the center columns 141a and 141b of the
tension ties 140a and 140b are solid, or include no passageway to
permit the flow of fluid through the column 141a and 141b. Instead,
the center columns 141a and 141b have an outer diameter less than
an inner diameter of openings 112 in the main plates 110, allowing
fluid to flow through the openings 112. In such an embodiment, an
outer diameter of the center columns 141a and 141b may be less than
an outer diameter of the top connectors 143a and 143b. In
alternative embodiments, the center columns 141a and 141b may have
passageways to permit fluid flow through the center columns 141a
and 141b and openings to permit the fluid to flow from the center
columns 141a and 141b into either the openings 112 or directly into
cavities between the main plates.
[0027] FIG. 3 illustrates a connection between a tension tie 140
and the fluid fitting 150 and top end plate 120. In embodiments of
the invention, the fluid fitting 150 may include an outside surface
151 having a smaller outer diameter at a braze region 163, a larger
outer diameter at a pilot region 164, and a recess 153, also
referred to as a braze ring 153, located between the pilot region
164 and the braze region 163. The outer diameter surface 151 of the
fitting 150 is configured to fit within the inside diameter surface
145 of the tension tie 140. During brazing, the braze extends
through the braze gap in the braze region 163 to maintain a strong
connection between the fluid fitting 150 and the tension tie
140.
[0028] The top connector 143 of the top end plate 120 may have an
inside surface 121 having a larger inner diameter at a braze region
162, a smaller inner diameter at a pilot region 162, and a recess
147, also referred to as a braze ring 147, located between the
pilot region 162 and the braze region 162. The outer diameter
surface 146 of the tension tie 140 is configured to fit within the
inside diameter surface 121 of the top end plate 120. During
brazing, the braze extends through the braze gap in the braze
region 161 to maintain a strong connection between the tension tie
140 and the top end plate 120.
[0029] FIG. 3 also illustrates main plates 110a and 110d on which
the top end plate 120 is stacked. In addition, FIG. 3 illustrates
the opening 142 and center column 141 of the tension tie 140. In
the embodiment illustrated in FIG. 3, the braze rings 153 and 147
are controlled spaces where braze material is stored precisely.
During brazing, the braze material flows through the braze regions
162 and 163 having predetermined widths to maintain braze strength.
In some embodiments, the outer surface 151 of the fluid fitting
150, the inner surface 145 of the tension tie 140, the outer
surface 146 of the tension tie 140 and the inner surface 121 of the
top end plate 120 are all parallel to each other, both in the braze
region 161 and in the pilot region 164.
[0030] FIGS. 4 to 7 illustrate tension ties according to some
embodiments. As illustrated in FIG. 4, in one embodiment, the
tension tie 440 includes a top connector 443, a bottom connector
444 and a center column 441 between the top connector 443 and
bottom connector 444. The center column 441 includes openings 445
along the length of the center column 441. The openings 445 may be
small holes, for example. Fluid enters the top connector 443 and
the center column 441 and exits from the holes 445 in the center
column 441 into a stack of main plates of a plate heat exchanger.
In the embodiment of FIG. 4, the top connector 443 has an outer
diameter that is larger than an outer diameter of the center column
441. In one embodiment, the top connector 443 does not include
openings to permit fluid flow into an opening formed in stacked
main plates. Instead, all of the fluid that flows into or out from
the tension tie 440 flows through the holes 445 and the center
column 441. In another embodiment, openings may also be provided in
the top connector 443. The center column 441 may have an outer
diameter less than an inner diameter of a channel formed by
openings in a stack of main plates, permitting fluid to flow to and
from the holes 445 in the center column 441 and the channel formed
by the openings in the stack of main plates.
[0031] As illustrated in FIG. 5, in one embodiment, the tension tie
540 includes a top connector 543, a bottom connector 544 and a
center column 545 between the top connector 543 and bottom
connector 544. The center column 541 includes openings 545 along
the length of the center column 541. The openings 545 may be
vertical slots, for example. Fluid enters the top connector 543 and
the center column 541 and exits from the vertical slots 545 in the
center column 541 into a stack of main plates of a plate heat
exchanger. In the embodiment of FIG. 5, the top connector 543 has
an outer diameter that is larger than an outer diameter of the
center column 541. In one embodiment, the top connector 543 does
not include openings to permit fluid flow into an opening formed in
stacked main plates. Instead, all of the fluid that flows into or
out from the tension tie 540 flows through the vertical slots 545
and the center column 541. In another embodiment, openings may also
be provided in the top connector 543. The center column 541 may
have an outer diameter less than an inner diameter of a channel
formed by openings in a stack of main plates, permitting fluid to
flow to and from the vertical slots 545 in the center column 541
and the channel formed by the openings in the stack of main
plates.
[0032] As illustrated in FIG. 6, in one embodiment, the tension tie
640 includes a top connector 643, a bottom connector 644 and a
center column 641 between the top connector 643 and bottom
connector 644. The center column 641 includes openings 645 along
the length of the center column 641. The openings 645 may be fluted
slots, for example. Fluid enters the top connector 643 and the
center column 641 and exits from the fluted slots 645 in the center
column 641 into a stack of main plates of a plate heat exchanger.
In the embodiment of FIG. 6, the top connector 643 has an outer
diameter that is larger than an outer diameter of the center column
641. In one embodiment, the top connector 643 does not include
openings to permit fluid flow into an opening formed in stacked
main plates. Instead, all of the fluid that flows into or out from
the tension tie 640 flows through the fluted slots 645 and the
center column 641. In another embodiment, openings may also be
provided in the top connector. The center column 641 may have an
outer diameter less than an inner diameter of a channel formed by
openings in a stack of main plates, permitting fluid to flow to and
from the holes 645 in the center column 641 and the channel formed
by the openings in the stack of main plates.
[0033] As illustrated in FIG. 7, in one embodiment, the tension tie
740 includes a top connector 743, a bottom connector 744 and a
center column 741 between the top connector 743 and bottom
connector 744. The center column 741 may be a cylinder that
includes openings 745 along the length of the center column 741.
The openings 745 may be small holes aligned to fin passages, or
cavities between main plates, for example. Fluid enters the top
connector 743 and the center column 741 and exits from the small
holes 745 in the center column 741 into a stack of main plates of a
plate heat exchanger. In one embodiment, an outer diameter of the
center column 741 is substantially the same as an inner diameter of
a channel formed by openings in a stack of main plates. In other
words, the center column 741 may have an outer diameter such that
the center column 741 fits snugly in the channel formed by the
openings. In such an embodiment, fluid may not be permitted to flow
through the channel formed by the openings in the stack of main
plates outside the center column 741. In other words, in one
embodiment, substantially all of the fluid that flows in cavities
between main plates in the stack of main plates flows directly out
from or into the holes 745 and the center column 741. In one
embodiment, the outer diameter of the center column 741 is bonded
to an inner diameter of the openings in the main plates defining
the channel by welding or brazing, thereby preventing fluid flow
through the channel, other than through the center column 741.
[0034] In embodiments of the present invention, tension ties are
provided between a top end plate and bottom end plate of a plate
heat exchanger. The tension ties include fluid fitting mount
portions to receive fluid fittings. The tension ties include
openings to permit fluid from the fluid fittings to flow into a
main plate stack and out from the main plate stack. The tension
ties strengthen the plate heat exchanger while reducing the need to
form the top and bottom end plates with extra material, thereby
reducing a weight of the plate heat exchanger. In addition, since
the fluid fittings are positioned inside the tension ties, the
fluid fittings may be precisely located, even if the top end plate
is subject to movement. In addition, the thicknesses of braze
material in critical locations is controlled to maintain a high and
consistent braze strength.
[0035] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
* * * * *