Abstract:
A marine engine fresh water cooling system and a marine vessel using a coolant system for use on double bottomed hulls or single hulled vessels which has a unique flange and bushing combination.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an improved device for cathodic protection of dissimilar metals on heat exchangers for fresh water cooling of marine engines. 
     As is well known, internal combustion engines are frequently employed for powering watercraft. It is the normal practice, particularly in connection with inboard engines, that engine coolant water is cooled by circulating the hot water through a heat exchanger secured to the exterior of the hull using flanges. Sea water cools the hot engine water while contained within the heat exchanger thereby providing cooler water which is then recirculated back to the engine, see, for example, U.S. Pat. 4,991,546 which is incorporated by reference. 
     These heat exchanges are very helpful, but difficulty has existed in the flange attachment for a double-hulled ship, because of corrosion. The present invention has been developed to reduce corrosion and improve cathodic protection for the flange used to secure the heat exchanger outlet to a vessel. 
     SUMMARY OF TIRE INVENTION 
     The invention relates to a cooling system for a fresh water cooled marine engine, comprising of a heat exchanger disposed in seawater for cooling heated fresh water from a marine engine; an inlet to said heat exchanger for receiving heated fresh water from said marine engine; an outlet from said heat exchanger for discharging cooled fresh engine water from said heat exchanger; said outlet having a central conduit, a gasket, a flange, a plurality of studs and a bushing; said outlet passing through a hull of a vessel; and said studs being covered by a bushing having a tube and a faceplate 
     The invention also relates to a vessel having a marine engine is provided with which fresh water is used as coolant for the engine and then circulated by means of cooling pump to a heat exchanger. Heated fresh water is passed from the engine into a conduit to the heat exchanger by means of this pump. The pump delivers the hot water to an inlet for the engine heat exchanger, as which is affixed to the hull of the boat. A flange is used to secure the inlet conduit. The heated fresh water circulates through an external heat exchanger, which cools the hot water by exposure to seawater in which the engine water heat exchanger is located. 
     The heated fresh engine water does not mix in the seawater in which the vessel is operating and once cooled, the cooled fresh water is circulated back into the engine through a second port, which is flanged, to the hull. 
     The present invention relates to an improved flange construction for use to and from the heat exchanger having a unique bushing for securing the flange to the hull. 
     It is an object of this invention to provide an improved cooling system for a marine engine that will be easily installed in single or double hulled vessels to reduce corrosion and still insure a proper and good seal between the heat exchanger and the hull. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an expanded view of the bushing and flange system. 
     FIG. 2 is a detailed view of the flange and stud combination usable on the bottom of a vessel. 
     FIG. 3 is a top view of the engine fresh water marine engine heat exchanger, showing the flange and stud combination. 
     FIG. 4 is a side view of the plange of FIG.  3 . 
     FIG. 5 is a side view of the intermediate attaching means using the bushing of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the heat exchanger flange  2  has a plurality of studs  12  for securing the heat exchanger to the hull of a vessel. FIG. 2 shows a hull  6  through which the outlet conduits  8  pass. The outlet conduits contain the cooled engine water from the heat exchanger  10 . In the most preferred embodiment, the heat exchanger flange  2  is approximately 1 inch thick, but the flange can range in thickness from 0.5 inches to 3 inches in thickness and remain usable in this invention. In the preferred embodiment, the heat exchanger flange  2  is made from a corrosion resistant material. Other coated metals can be used, and graphite composites may even be usable in the present invention. 
     Returning to FIG. 1, the flange  2  has a plurality of holes for receiving studs  12  from the heat exchanger  10 . In a preferred embodiment, a gasket  14 , such as a ⅛ inch gasket by Femstrum is disposed between the heat exchanger  10  and the flange  2 . Over the stud  12  is disposed a one piece bushing having a tube  16  and a face plate  18 . The bushing is preferably made of a phenolic compound or strong composite material. The shaft  16  extends entirely over the stud  12  to the gasket  14  thereby preventing cathodic degradation, and the deterioration of the flange  2  due to exposure to a corrosive environment. The bushing is hollow and can be secured using a bead  20  of permatex red, or other similar non-hardening sealant between the edge of the bushing that meets the gasket and the stud. 
     Over the bushing plate  18 , a flat washer  22 , preferably a phenolic compound or nylon can be placed and secured with a nut or similar tightening means  24 . In the most preferred embodiment, a nylok nut can be used, such as those provided from Fermnstrum. 
     Additionally, locktite, or a similar non-hardening sealant can be placed over the ends of the stud  12  which engages the nut  24 . In the most preferred embodiment, the non-hardening blue sealant can be used. 
     The stud can be threaded for engagement with the nylok nut. In the most preferred embodiment, the stud has about one inch to two inches of threads for securing to the nut. 
     FIG. 3 shows the heat exchanger  10  secured with two identical flanges  2  and  3 . 
     FIG. 4 shows a side view of the mating flange  2  secured to the hull of the vessel  6 , as shown in FIG.  2 . In this side view, the flange is shown with  4  studs visible,  26 ,  28 ,  30  and  32 . In one embodiment, the studs each have a nut,  34 ,  36 ,  38  and  40  which is preferably a lock nut. In a preferred embodiment, the flange has 8 studs, each 3 inches long spaced apart in equal distances. However, a flange with various numbers of studs can be used depending on the size of the flanges. The mating flange  2  can be a carbon steel with the ability to slip onto a 4 inch pipe with a 4.57 inch ANSI pipe. 
     The invention is specifically directed to a marine vessel, comprising of a fresh water cooled engine; a heat exchanger for cooling the fresh water from the fresh water cooled engine, said heat exchanger being fixed to the exterior of the hull of said marine vessel using support means; a flange system for affixing said heat exchanger to said vessel hull comprising of a flange, a plurality of studs, a plurality of bushings, each bushing covering each stud, each bushing having a tube and a face plate, and wherein said tube extends the entire length of said stud; a plurality of gaskets, each gasket disposed between said bushing and said heat exchanger; a plurality of lock nuts, each lock nut for securing each bushing and flange into said stud. 
     Additionally, the heat exchanger include intermediate support members as shown in FIG.  5 . FIG. 5 shows heat exchanger  10 , a gasket  32 , and the intermediate support member  34 . A bolt  36  with a nut  38 , which is preferably a lock nut, holds a washer  40  on top of flanged bushing  42  top of flanged bushing  42  which has a one piece construction of a face plate  44  and a tube  46 . The bolt attaches to a clip  48  extended from the hull of a ship. In this embodiment, the lock nut is preferably stainless steel and the washer  40  and flanged bushing  42  are phenolic material, such as nylon. The tube  46  extends the length of the bolt  36  to the gasket  32 . 
     Sealant, preferably non-hardening can be used between the flanged bushing and the gasket, and the bolt and nut. 
     It should be readily apparent from the foregoing description that the embodiments of the invention illustrated and described are very effective in insuring an adequate cathodic protected cooling system for a marine engine. Although a number of embodiments of the invention have been illustrated and described, various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.