U.S. patent application number 11/484171 was filed with the patent office on 2010-04-08 for liquid to liquid heat exchanger for a marine engine cooling system.
This patent application is currently assigned to Brunswick Corporation. Invention is credited to Ritchie C. Griffin, Matthew W. Jaeger, Brian D. Simpson.
Application Number | 20100084111 11/484171 |
Document ID | / |
Family ID | 42074863 |
Filed Date | 2010-04-08 |
United States Patent
Application |
20100084111 |
Kind Code |
A1 |
Jaeger; Matthew W. ; et
al. |
April 8, 2010 |
Liquid to liquid heat exchanger for a marine engine cooling
system
Abstract
A liquid to liquid heat exchanger for a marine engine cooling
system disposes a tube bundle within a non-metallic shell, provides
a thermostat within an integral portion of the shell, uses bolts
that both push and pull respective end caps when rotated, and in
one embodiment provides an integral deaeration reservoir to remove
entrained gases from a liquid of a closed cooling system.
Inventors: |
Jaeger; Matthew W.;
(Stillwater, OK) ; Simpson; Brian D.; (Yale,
OK) ; Griffin; Ritchie C.; (Bradenton, FL) |
Correspondence
Address: |
WILLIAM D. LANYI
MERCURY MARINE, W6250 PIONEER ROAD P.O. BOX 1939
FOND DU LAC
WI
54936-1939
US
|
Assignee: |
Brunswick Corporation
|
Family ID: |
42074863 |
Appl. No.: |
11/484171 |
Filed: |
July 11, 2006 |
Current U.S.
Class: |
165/41 ;
123/41.01; 165/104.31; 165/164; 165/51; 165/67 |
Current CPC
Class: |
F28D 1/022 20130101;
B63H 21/383 20130101; F01P 3/207 20130101; F28F 9/22 20130101; F28F
2275/20 20130101; F28F 27/02 20130101; F28D 7/16 20130101; F28F
2265/18 20130101; F01P 2050/06 20130101; F28F 9/0219 20130101; F01P
11/028 20130101 |
Class at
Publication: |
165/41 ; 165/51;
165/67; 165/104.31; 165/164; 123/41.01 |
International
Class: |
F01P 3/20 20060101
F01P003/20; B63H 21/38 20060101 B63H021/38; F28D 15/00 20060101
F28D015/00; F28F 9/00 20060101 F28F009/00; F28F 9/013 20060101
F28F009/013 |
Claims
1. A liquid to liquid heat exchanger for a marine engine cooling
system, comprising: a nonmetallic shell comprising first and second
end caps which are attached to a cylindrical portion of said
nonmetallic shell; a tube bundle disposed within said nonmetallic
shell, said tube bundle comprising a plurality of tubes, the
internal cavities of said plurality of tubes being connected in
fluid communication with each other to define a first path for a
first liquid, said nonmetallic shell and said tube bundle being
configured to cooperate with each other to define a second path for
a second liquid which directs said second liquid to flow in thermal
contact with outside surfaces of said plurality of tubes and which
causes said first and second liquids to be disposed in thermal
communication with each other; a first bolt which extends through a
portion of said first end cap and is attached in threaded
engagement with said tube bundle, said first bolt being configured
to urge said first end cap toward said cylindrical portion when
said first bolt is rotated into said threaded engagement with said
tube bundle and to urge said first end cap away from said
cylindrical portion when said first bolt is rotated out of said
threaded engagement with said tube bundle, said first bolt being
configured to fail in torsional shear at a preselected location
upon an application of a predetermined magnitude of torque to a
head of said bolt, said preselected location being axially
displaced from said tube bundle; and wherein said bolt has a groove
therein at said preselected location, and axially spaced from the
location of said threaded engagement.
2. The heat exchanger of claim 1, wherein: said groove is a failure
groove; said bolt has one or more other sealing grooves therein
each receiving a respective O-ring; and said failure groove has a
greater depth than each of said one or more sealing grooves.
3. The heat exchanger of claim 2, wherein: said one or more sealing
grooves are axially spaced between said failure groove and said
location of said threaded engagement, such that said failure groove
is on one axial side of said one or more sealing grooves, and said
location of said threaded engagement is on the other distally
opposite axial side of said one or more sealing grooves, such that
upon torsional shear failure at said failure groove at said
preselected location, the sealing at said one or more sealing
grooves and their respective O-rings remains intact.
4. The heat exchanger of claim 2, wherein: said first path is
connectable in fluid communication with a pump for drawing water
from a body of water in which said marine engine is operated.
5. The heat exchanger of claim 1, further comprising: a second bolt
which extends through a portion of said second end cap and is
attached in threaded engagement with said tube bundle, said second
bolt being configured to urge said second end cap toward said
cylindrical portion when said second bolt is rotated into said
threaded engagement with said tube bundle and to urge said second
end cap away from said cylindrical portion when said second bolt is
rotated out of said threaded engagement with said tube bundle.
6. (canceled)
7. The heat exchanger of claim 5, wherein: said first and second
bolts are rotatably attached to said first and second end caps,
respectively.
8. The heat exchanger of claim 1, further comprising: a thermostat
disposed in thermal communication with said second liquid and in
serial association with said second path, said thermostat being
disposed within a thermostat housing which is attached to said
nonmetallic shell.
9-20. (canceled)
21. A liquid to liquid heat exchanger for a marine engine cooling
system, comprising: a nonmetallic shell comprising first and second
end caps which are attached to a cylindrical portion of said
nonmetallic shell; a tube bundle disposed within said nonmetallic
shell, said tube bundle comprising a plurality of tubes, the
internal cavities of said plurality of tubes being connected in
fluid communication with each other to define a first path for a
first liquid, said first path being connectable in fluid
communication with a pump for drawing water from a body of water in
which said marine engine is operated, said nonmetallic shell and
said tube bundle being configured to cooperate with each other to
define a second path for a second liquid which directs said second
liquid to flow in thermal contact with outside surfaces of said
plurality of tubes and which causes said first and second liquids
to be disposed in thermal communication with each other, said
second path being connectable in fluid communication with an
internal cooling jacket of said marine engine; a thermostat
disposed in thermal communication with said second liquid and in
serial association with said second path, said thermostat being
disposed within a thermostat housing which is attached to said
nonmetallic shell, said thermostat housing being attached to a
conduit which is formed as an integral portion of said nonmetallic
shell, a first flange being formed as an integral part of said
conduit and shaped to be attached to a second flange which is
formed as an integral part of said thermostat housing; a first bolt
which extends through a portion of said first end cap and is
attached in threaded engagement with said tube bundle, said first
bolt being configured to urge said first end cap toward said
cylindrical portion when said first bolt is rotated into said
threaded engagement with said tube bundle and to urge said first
end cap away from said cylindrical portion when said first bolt is
rotated out of said threaded engagement with said tube bundle, said
first bolt being configured to fail in torsional shear at a
preselected location on said first bolt upon an application of a
predetermined magnitude of torque to a head of said bolt, said
preselected location being axially displaced from said tube bundle;
a second bolt which extends through a portion of said second end
cap and is attached in threaded engagement with said tube bundle,
said second bolt being configured to urge said second end cap
toward said cylindrical portion when said second bolt is rotated
into said threaded engagement with said tube bundle and to urge
said second end cap away from said cylindrical portion when said
second bolt is rotated out of said threaded engagement with said
tube bundle, said first and second bolts are rotatably attached to
said first and second end caps, respectively; and wherein said bolt
has a groove therein at said preselected location and axially
spaced from the location of said threaded engagement, said groove
is a failure groove, said bolt has one or more other sealing
grooves therein each receiving a respective O-ring, said failure
groove has a greater depth than each of said one or more sealing
grooves, said one or more sealing grooves are axially spaced
between said failure groove and said location of said threaded
engagement, such that said failure groove is on one axial side of
said one or more sealing grooves, and said location of said
threaded engagement is on the other distally opposite axial side of
said one or more sealing grooves, such that upon torsional shear
failure at said failure groove at said preselected location, the
sealing at said one or more sealing grooves and their respective
O-rings remains intact.
22. A liquid to liquid heat exchanger for a marine engine cooling
system, comprising: a nonmetallic shell comprising first and second
end caps which are attached to a cylindrical portion of said
nonmetallic shell; a tube bundle disposed within said nonmetallic
shell, said tube bundle comprising a plurality of tubes, the
internal cavities of said plurality of tubes being connected in
fluid communication with each other to define a first path for a
first liquid, said first path being connectable in fluid
communication with a pump for drawing water from a body of water in
which said marine engine is operated, said nonmetallic shell and
said tube bundle being configured to cooperate with each other to
define a second path for a second liquid which directs said second
liquid to flow in thermal contact with outside surfaces of said
plurality of tubes and which causes said first and second liquids
to be disposed in thermal communication with each other; a
deaeration reservoir formed as an integral part of said nonmetallic
shell, said deaeration reservoir being connected in fluid
communication with said second path to direct a portion of said
second liquid through said deaeration reservoir; a thermostat
disposed in thermal communication with said second liquid and in
serial association with said second path, said thermostat being
disposed within a thermostat housing which is attached to said
nonmetallic shell, said second path is connectable in fluid
communication with an internal cooling jacket of said marine
engine, said second liquid comprising ethylene glycol; a first bolt
which extends through a portion of said first end cap and is
attached in threaded engagement with said tube bundle, said first
bolt being configured to urge said first end cap toward said
cylindrical portion when said first bolt is rotated into said
threaded engagement with said tube bundle and to urge said first
end cap away from said cylindrical portion when said first bolt is
rotated out of said threaded engagement with said tube bundle, said
first bolt being configured to fail in torsional shear at a
preselected location on said first bolt upon an application of a
predetermined magnitude of torque to a head of said bolt, said
preselected location being axially displaced from said tube bundle;
a second bolt which extends through a portion of said second end
cap and is attached in threaded engagement with said tube bundle,
said second bolt being configured to urge said second end cap
toward said cylindrical portion when said second bolt is rotated
into said threaded engagement with said tube bundle and to urge
said second end cap away from said cylindrical portion when said
second bolt is rotated out of said threaded engagement with said
tube bundle, said first and second bolts being rotatably attached
to said first and second end caps, respectively; a first bolt which
extends through a portion of said first end cap and is attached in
threaded engagement with said tube bundle, said first bolt being
configured to urge said first end cap toward said cylindrical
portion when said first bolt is rotated into said threaded
engagement with said tube bundle and to urge said first end cap
away from said cylindrical portion when said first bolt is rotated
out of said threaded engagement with said tube bundle; a second
bolt which extends through a portion of said second end cap and is
attached in threaded engagement with said tube bundle, said second
bolt being configured to urge said second end cap toward said
cylindrical portion when said second bolt is rotated into said
threaded engagement with said tube bundle and to urge said second
end cap away from said cylindrical portion when said second bolt is
rotated out of said threaded engagement with said tube bundle, said
first and second bolts being rotatably attached to said first and
second end caps, respectively; and at least one of said bolts has a
groove therein at said preselected location and axially spaced from
the location of said threaded engagement, said groove is a failure
groove, said one bolt has one or more other sealing grooves therein
each receiving a respective O-ring, said failure groove has a
greater depth than each of said one or more sealing grooves, said
one or more sealing grooves are axially spaced between said failure
groove and said location of said threaded engagement, such that
said failure groove is on one axial side of said one or more
sealing grooves, and said location of said threaded engagement is
on the other distally opposite axial side of said one or more
sealing grooves, such that upon torsional shear failure at said
failure groove at said preselected location, the sealing at said
one or more sealing grooves and their respective O-rings remains
intact.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is generally related to a heat
exchanger and, more particularly, to a heat exchanger for a marine
engine in which heat is exchanged between a coolant flowing within
a closed cooling system and water drawn from a body of water and
subsequently returned to that body of water after passing through
the heat exchanger.
[0003] 2. Description of the Related Art
[0004] Many types of heat exchangers are known to those skilled in
the art for use in marine engine cooling systems. Although some
marine engine cooling systems are open loop systems which circulate
water, drawn from a body of water in which a marine vessel is
operating, through all cooling passages of the propulsion system,
other systems incorporate partially closed loop systems which
circulate a coolant, such as ethylene glycol, through certain
cooling passages of an engine and use water drawn from the body of
water to remove heat from the coolant of the closed portion of the
system. Those partially closed cooling systems typically
incorporate liquid to liquid heat exchangers.
[0005] U.S. Pat. No. 4,360,350, which issued to Grover on Nov. 23,
1982, describes a hollow keel heat exchanger for marine vessels.
The marine vessel has a hull with a hollow keel, generally of a
non-metallic material, and an engine cooled by a closed loop, fresh
water circulating cooling system. The keel is formed as a hollow
keel chamber which has entry and exit apertures for circulating sea
water through the chamber. A portion of the fresh water cooling
system passes through the hollow keel chamber in heat exchange
relation to the sea water providing a simple and efficient heat
exchanger for cooling the engine.
[0006] U.S. Pat. No. 4,520,868, which issued to Grawey on Jun. 4,
1985, describes a heat exchanger. It has a plurality of
longitudinally extending tubes disposed within a shell and includes
an elastomeric end plate and means for compressing the elastomeric
end plate and expanding the plate in the longitudinal direction and
internal vibration-damping baffle plates. It avoids the problems of
the prior art by providing an end wall assembly for a heat
exchanger wherein an elastomeric end plate is mounted under
compression in only a direction transversed to the tubes passing
through the plate. The elastomeric end plate is not restrained in a
longitudinal direction with respect to the tubes and as a result of
the transversely applied compression force, the end plate is
expanded in the longitudinal direction.
[0007] U.S. Pat. No. 4,643,249, which issued to Grawey on Feb. 17,
1987, describes a heat exchanger baffle plate. The baffle plate has
a plurality of openings for receiving a plurality of longitudinally
extending tubes and is disposed within a shell and is constructed
of a vibration damping material.
[0008] U.S. Pat. No. 4,674,293, which issued to Clarke et al. on
Jun. 23, 1987, describes a marine air conditioning heat exchanger.
The heat exchanger is intended for use in a marine air conditioning
system and is configured to provide the maximum possible heat
transfer surface for the air being conditioned. The refrigerant
coils and associated fins form the heat exchanger banks as usual,
but instead of a single vertical bank, two banks are positioned at
an angle to each other.
[0009] U.S. Pat. No. 5,004,042, which issued to McMorries et al. on
Apr. 2, 1991, discloses a closed loop cooling system for a marine
engine. A marine power system has closed loop cooling and includes
a marine engine having a cooling fluid passage defined therethrough
through which a cooling fluid stream may pass. A shell and tube
heat exchanger has a tube side flow path and a shell side flow path
defined therein. Cooling fluid conduits connect the cooling fluid
passage from the marine engine to the tube side flow path so that
the cooling fluid stream from the engine is directed through the
tube side flow path of the heat exchanger. A raw water supply
system directs a raw water stream from a body of water through the
shell side flow path and then back to the body of water. The heat
exchanger includes an outer housing and a tube bundle receiver in
the outer housing. The outer housing is comprised of a shell and
first and second end caps. The tube bundle includes a plurality of
straight parallel tubes held between two spaced bundle bases. The
housing and the bundle bases are constructed of non-metallic
corrosion resistant materials. The tubes are constructed of
metallic materials suitable for efficient heat transfer. The tubes
are arranged in a plurality of substantially similar groups, each
group being located in one of a plurality of cross-sectional
areas.
[0010] The patents described above are hereby expressly
incorporated by reference in the description of the present
invention.
SUMMARY OF THE INVENTION
[0011] A liquid to liquid heat exchanger for a marine engine
cooling system, made in accordance with a preferred embodiment of
the present invention, comprises a non-metallic shell comprising
first and second end caps which are attached to a cylindrical
portion of the non-metallic shell, a tube bundle disposed within
the non-metallic shell, wherein the tube bundle comprises a
plurality of tubes. The internal cavities of the plurality of tubes
are connected in fluid communication with each other to define a
first path for a first liquid. The non-metallic shell and the tube
bundle are configured to cooperate with each other to define a
second path for a second liquid which directs the second liquid to
flow in thermal contact with outer surfaces of the plurality of
tubes and which causes the first and second liquids to be disposed
in thermal communication with each other.
[0012] One embodiment of the present invention further comprises a
first bolt which extends through a portion of the first end cap and
is attached in threaded engagement with the tube bundle. The first
bolt is configured to urge the first end cap toward the cylindrical
portion of the non-metallic shell when the first bolt is rotated
into the threaded engagement with the tube bundle and to urge the
first end cap away from the cylindrical portion of the non-metallic
shell when the first bolt is rotated out of threaded engagement
with the tube bundle.
[0013] In a preferred embodiment of the present invention, the
second path is connectable in fluid communication with an internal
cooling jacket of the marine engine. The second liquid can comprise
an ethylene glycol mixture. The first path in a preferred
embodiment of the present invention is connectable in fluid
communication with a pump for drawing water from a body of water in
which the marine engine is operated.
[0014] In a preferred embodiment of the present invention, it
further comprises a second bolt which extends through a portion of
the second end cap and is attached in threaded engagement with a
tube bundle. The second bolt is configured to urge the second end
cap toward the cylindrical portion of the non-metallic shell when
the second bolt is rotated into threaded engagement with the tube
bundle and to urge the second end cap away from the cylindrical
portion of the non-metallic shell when the second bolt is rotated
out of threaded engagement with the tube bundle.
[0015] In a particularly preferred embodiment of the present
invention, the first and second bolts are configured to fail in
torsional shear upon an application of a predetermined magnitude of
torque to a head of either bolt. The first and second bolts are
rotatably attached to the first and second end caps, respectively,
in a preferred embodiment of the present invention. The bolts are
free to rotate relative to their associated end cap but are
restricted from moving axially, in a direction parallel to the
centerline of the bolts, relative to their associated end caps.
[0016] In a particularly preferred embodiment of the present
invention, a thermostat is disposed in thermal communication with
the second liquid and in serial association with the second path. A
thermostat is disposed within a thermostat housing which is
attached to the non-metallic shell. The thermostat housing is
attached to a conduit which is formed as an integral portion of the
non-metallic shell. A first flange is formed as an integral part of
the conduit and shaped to be attached to a second flange which is
formed as an integral part of the thermostat housing.
[0017] In one preferred embodiment of the present invention, a
deaeration reservoir is formed as an integral part of the
non-metallic shell. The deaeration reservoir is connected in fluid
communication with the second path in order to direct a portion of
the second liquid through the deaeration reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be more fully and completely
understood from a reading of the description of the preferred
embodiment in conjunction with the drawings, in which:
[0019] FIG. 1 is an exploded isometric view of a heat exchanger
made in accordance with one embodiment of the present
invention;
[0020] FIG. 2 is an assembled isometric view of the heat exchanger
shown in FIG. 1;
[0021] FIG. 3 is an isometric view of a tube bundle contained
within the heat exchanger of the present invention;
[0022] FIG. 4 is a section view of the tube bundle of FIG. 3;
[0023] FIG. 5 is a section view of a bolt used in conjunction with
a preferred embodiment of the present invention;
[0024] FIGS. 6 and 7 are isometric exploded views of end caps of a
preferred embodiment of the present invention;
[0025] FIG. 8 is an isometric view of an embodiment of the present
invention that incorporates an integral deaeration reservoir;
[0026] FIG. 9 is a section view of the embodiment illustrated in
FIG. 8; and
[0027] FIG. 10 is a section view taken through a heat exchanger
made in accordance with a preferred embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] Throughout the description of the preferred embodiment of
the present invention, like components will be identified by like
reference numerals.
[0029] FIG. 1 is an exploded isometric view of a liquid to liquid
heat exchanger made in accordance with one preferred embodiment of
the present invention. A non-metallic shell 10 comprises first and
second end caps, 11 and 12, which are attached to a cylindrical
portion 14 of the non-metallic shell. In a preferred embodiment,
both end caps are also non-metallic. A tube bundle 20, which will
be described in greater detail below, is disposed within the
non-metallic shell 10. The tube bundle 20 comprises a plurality of
tubes.
[0030] With continued reference to FIG. 1, a coolant inlet 26 and
coolant outlet 28 are provided. A water inlet 30 and a water outlet
32 are provided to introduce a flow of water, from a body of water
in which a marine engine is operated, through the internal cavities
of the plurality of tubes contained within the tube bundle 20. The
coolant inlet 26 is connected in fluid communication with the
volume surrounding the plurality of tubes 20 within the
non-metallic shell 10. This coolant, which can comprise ethylene
glycol, is then eventually directed to the coolant outlet 28.
[0031] FIG. 2 is an isometric view of the heat exchanger with the
individual components assembled. FIG. 3 shows the tube bundle 20
and FIG. 4 is a section view taken along a plane that intersects a
central axis of the tube bundle 20.
[0032] With continued reference to FIGS. 1-4, the tube bundle 20 is
disposed within the non-metallic shell 10. The tube bundle 20
comprises a plurality of tubes 38 that are held in position by
their insertion through holes that extend through the thickness of
a plurality of baffles 40. The tubes 38 also extend through holes
formed in through the thickness of elastomeric tube sheets 42
located at the axial ends of the tube bundle 20.
[0033] With continued reference to FIGS. 1-4, a brass rod 46
extends along a central axis of the tube bundle 20. This brass rod
is threaded at both ends to accept bolts which will be described in
greater detail below. The internal cavities of the plurality of
tubes 38 define a first path for a first liquid, such as water
drawn from a lake or ocean in which the marine engine is being
operated. The non-metallic shell 10 and the tube bundle 20 are
configured to cooperate with each other to define a second path for
a second liquid, such as a coolant comprising an ethylene glycol
mixture, which directs the second liquid to flow in thermal contact
with outside surfaces of the plurality of tubes 38. This causes the
first and second liquids to be disposed in thermal communication
with each other through the thickness of the walls of the plurality
of tubes 38. The arrows in FIG. 4 indicate the second path of the
second liquid.
[0034] With continued reference to FIGS. 1-4, the first and second
end caps, 11 and 12, are attached to the tube bundle 20 by bolts
which are identified by reference numeral 50 in FIG. 1. FIG. 5 is a
section view of a bolt 50. FIGS. 6 and 7 are isometric views of the
first 11 and second 12 end caps, respectively.
[0035] With reference to FIGS. 5-7, the bolts 50 are threaded at a
distal end 54 and have a head 56 formed at the opposite end to
facilitate the threading of the bolt 50 into and out of the
threaded ends of the brass rod 46 which are identified by reference
numeral 58 in FIG. 4. The bolts 50 are provided with two grooves,
61 and 62 which are shaped to receive O-rings, 71 and 72,
respectively. It should be noted that groove 61 is deeper than
groove 62. This greater depth of groove 61 is intentionally
provided so that the bolt 50 will fail due to torsional shear at a
predetermined magnitude of torque. That predetermined magnitude is
selected to assure that the bolt will fail in the region of groove
61 prior to the threads 58 of the brass rod 46. It should be
understood that the regions proximate the interface between the
threads on the distal end 54 of the bolts 50 and the threads 58
within the brass rod 46 are located in a region that is exposed to
water drawn from a body of water. This can lead to corrosion at the
interface of the threads, particularly when the heat exchanger is
used in a saltwater environment The screw failing in this manner
results in a less expensive repair as compared to an internal
thread failure in the brass rod.
[0036] With continued reference to FIGS. 5-7, a third groove 63 is
shaped to receive a snap ring 76 which retains the bolt 50 in the
axial position defined by the flange 78 on the bolt 50, the snap
ring 76 and the hole extending through the end caps, 11 and 12,
through which the bolts 50 are disposed. The configuration of the
bolts 50, in cooperation with the snap ring 76, performs a
significantly advantageous function. The bolts are configured to
urge the associated end cap, 11 or 12, toward the cylindrical
portion 14 of the non-metallic shell 10 when the bolt is rotated
into the threaded engagement with the threads 58 of the brass rod
46 shown in FIG. 4. This configuration also urges the associated
end cap, 11 or 12, away from the cylindrical portion 14 of the
non-metallic shell 10 when the bolt is rotated out of its threaded
engagement with the threads 58 in the brass rod 46 of the tube
bundle 20. As a result, this configuration of the bolt and snap
ring 76 assist the removal and replacement of the associated end
cap whether the end cap is being removed from the heat exchanger or
attached to the heat exchanger. The flange 78 of the bolt 50 and
the snap ring 76 in groove 63 can provide either a push force and a
pull force on the associated end cap, 11 or 12, to provide a
significant benefit during the removal and reattachment of the end
caps.
[0037] With continued reference to FIG. 1, a thermostat 80 is
disposed in thermal communication with the second liquid and in
serial association with the second path. The thermostat 80 is
disposed within a thermostat housing 82 that is attached to the
non-metallic shell 10. The thermostat housing 82 is attached to a
conduit 84 that is formed as an integral portion of the
non-metallic shell 10 in a particularly preferred embodiment of the
present invention. A first flange 91 is formed as an integral part
of the conduit 84 and shaped to be attached to a second flange 92
which is formed as an integral part of the thermostat housing 82.
The thermostat housing 82 can be bolted to the conduit 84 as shown
in FIG. 2. Flanges 91 and 92 are asymmetrical. This facilitates
assembly and assures that hose connection 26 is always correctly
oriented. Elastomeric seal 81, installed over the flange of
thermostat 80, seals the thermostat housing to the mating flange
interface.
[0038] For convenience in evacuating the air from the second fluid
circuit during the filling process, an opening 96 is provided at
the top portion of the cylindrical shell. A plug 97 is provided to
close the opening. A bypass conduit 99, shown in FIG. 9, is
provided to recirculate the coolant that does not flow past the
thermostat 80 and through the conduit 84.
[0039] FIGS. 8 and 9 show isometric and section views of an
alternative embodiment of the present invention. A deaeration
reservoir 100 is formed as an integral part of the non-metallic
shell 10 and, more particularly, as an integral part of the
cylindrical portion 14 of the non-metallic shell. The second liquid
can flow into the cavity defined by the deaeration reservoir 100
through an orifice 104 shown in FIG. 9 and extending through a wall
of the cylindrical portion 14 of the non-metallic shell 10 and also
through an inlet which is identified by reference numeral 106 in
FIG. 8. The second liquid can flow out of the deaeration reservoir
100 through conduit 110 shown in FIG. 8. The inlets and outlet of
the deaeration reservoir 100 are sized to assure a relatively slow
flow of the second liquid through the reservoir 100 in parallel to
the flow of the second liquid through the heat exchanging part of
the structure. This reduced velocity of flow allows gases to escape
from the second liquid and remain in the upper portion of the
deaeration reservoir 100. The cap 110 is configured to allow gases
to escape from the cavity 112 within the deaeration reservoir 100
when pressure exceeds a preselected magnitude. Through this method,
the gases are removed from the second liquid.
[0040] FIG. 10 is a section view of one end of the heat exchanger.
It shows a bolt 50 threaded into a threaded end 58 of the brass rod
46 with the O-rings (identified in FIGS. 6 and 7 by reference
numerals 71 and 72). The combination of the flange 78 and snap ring
76 provide mechanical advantage when the end cap is being attached
to the tube bundle 20 or removed therefrom. This operation is the
same for the bolts 50 used in conjunction with both end caps, 11
and 12.
[0041] With reference to FIGS. 1, 6 and 7, it should be understood
that the first liquid flows through the inside portions of the
tubes in a multi-pass manner. In other words, water entering the
raw water inlet 30 flows through a first compartment 111 and is
directed through a first group of tubes whose ends are disposed
proximate the first compartment 111. The first liquid then flows,
from left to right in FIG. 1, toward the second end cap 12. The
first liquid then flows into the compartment 112 of the second end
cap 12 and is turned back toward the left in FIG. 1. After the
first liquid travels from right to left in FIG. 1 and into the
third cavity 113 of the first end cap 11, it is again reversed so
that it flows back toward the second end cap 12 from the cavity
identified by reference numeral 114. Eventually, the first liquid
is again reversed at cavity 115 to flow again toward the right and
toward the second end cap 12 where it flows into the cavity
identified by reference numeral 116. From there, it flows out of
the outlet 32 to be returned to the body of water from which it was
originally drawn.
[0042] With reference to FIGS. 1 and 4, the exchange of heat occurs
with calories flowing from the second liquid, which flows along a
second path represented by the arrows in FIG. 4, to the first
liquid which flows in the manner described above in conjunction
with FIGS. 1, 6 and 7. In FIGS. 6 and 7, O-rings 120 provide a seal
between the end caps, 11 and 12, and the cylindrical portion 14 of
the non-metallic shell 10.
[0043] With reference to FIGS. 1-10, it can be seen that a liquid
to liquid heat exchanger for a marine engine cooling system made in
accordance with a preferred embodiment of the present invention
comprises a non-metallic shell 10 which comprises first and second
end caps, 11 and 12, which are attached to a cylindrical portion
14. A tube bundle 20 is disposed within the non-metallic shell 10.
The tube bundle comprises a plurality of tubes 38. The internal
cavities of the plurality of tubes 38 are connected in fluid
communication with each other to define a first path for a first
liquid, such as water drawn from a body of water. The non-metallic
shell 10 and the tube bundle 20 are configured to cooperate with
each other to define a second path, which is illustrated by arrows
in FIG. 4, for a second liquid, such as an ethylene glycol mixture,
which directs the second liquid to flow in thermal contact with
outside surfaces of the plurality of tubes 38 and which causes the
first and second liquids to be disposed in thermal communication
with each other. First and second bolts 50 extend through portions
of the first and second end caps, 11 and 12, and are attached in
threaded engagement with a brass rod 46 of the tube bundle 20. The
bolts are configured to urge the associated end caps toward the
cylindrical portion 14 when they are rotated into threaded
engagement with the tube bundle 20 and to urge the associated end
cap away from the cylindrical portion 14 when they are rotated out
of threaded engagement with the brass rod 46 of the tube bundle 20.
The second path of the second liquid is connectable in fluid
communication with an internal cooling jacket of the marine engine
and the second liquid, in a particularly preferred embodiment of
the present invention, can comprise an ethylene glycol mixture. The
first path, of the water drawn from the body of water, is
connectable in fluid communication with a pump for drawing water
from the body of water in which the marine engine is operated. The
connections between the heat exchanger and the engine and water
pump are very well known to those skilled in the art and will not
be further described herein. The bolts 50 are configured to fail in
torsional shear upon an application of a predetermined magnitude of
torque to a head 56 of the bolt 50. This failure is caused to occur
at the first slot 61 which is formed deeper than other slots of the
bolt 50. The bolts 50 are rotatably attached to the first and
second end caps, 11 and 12, respectively and are limited in their
axial movement relative to their associated end cap. A thermostat
80 is disposed in thermal communication with the second liquid and
in serial association with the second path. The thermostat is
disposed within a thermostat housing 82 which is attached to the
non-metallic shell 10. The thermostat housing 82 is attached to a
conduit 84 which is formed as an integral portion of the
non-metallic shell 10. A first flange 91 is formed as an integral
part of the conduit 84 and shaped to be attached to a second flange
92 which is formed as an integral part of the thermostat housing
82. In one embodiment of the present invention, a deaeration
reservoir 100 is formed as an integral part of the non-metallic
shell 10 and, more particularly, as an integral part of the
cylindrical portion 14 of the non-metallic shell. The deaeration
reservoir 100 is connected in fluid communication with the second
path, which is illustrated by arrows in FIG. 4, to direct a portion
of the second liquid through the deaeration reservoir 100.
[0044] Although the present invention has been described with
particular specificity and illustrated to show a plurality of
embodiments, it should be understood that alternative embodiments
are also within its scope.
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