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.

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.