Patent Publication Number: US-2005142959-A1

Title: Exhaust viverter nozzle

Description:
FIELD OF INVENTION  
      The present invention is directed to an exhaust diverter nozzle used in water cooling the exhaust of marine engines. The exhaust diverter nozzle diverts the exhaust cooling water in a manner which greatly enhances the vaporization of the water, thus cooling, at low engine rpm of 1600-2000 rpm.  
     BACKGROUND OF THE INVENTION  
      Inboard marine engines require exhaust systems to carry the hot exhaust to the exterior of the boat. Engines, especially diesel engines, generate a considerable amount of heat which is dissipated through the exhaust. The heat becomes a problem because the exhaust system is contained within the hull of the boat. Exhaust elbows are mounted to the exhaust manifold of the engine wherein seawater is added to the exhaust. The water channel usually externally jackets the circular exhaust pipe and mixes with the exhaust gas with a cooling effect. The more the water is atomized and vaporized the cooler the exhaust becomes. The cooling effect of vaporized water is best demonstrated in evaporative coolers which have existed since 1937. The exhaust elbow cooling system is most effective at high engine speeds wherein large volumes of seawater flow through the exhaust. Cooling the exhaust lines at low engine rpm speeds (1600-2000 rpm) is a problem because of the low volume of water. With low seawater flow through the exhaust elbow the seawater only flows through in the lower part of the exhaust elbow which produces very little atomization and vaporization of the water which is necessary for the vaporization cooling effect. The exhaust heat at low engine speeds has caused early deterioration of the silicone-acrylic exhaust tubes which are used more commonly with diesel engines. This is particularly evident in the wet exhaust system of the Nordhavn 35 coastal pilot which is designed to maximize working space of the engine room. The 5″ rubber exhaust hose is routed to the water lift box mounted in the Lazarett. The exhaust hose has a history of damage at low engine rpm (1600-2000 rpm), the reduced water flow through the exhaust elbow does not provide a water spray pattern for sufficient heat exchange of the exhaust gases.  
      In order to overcome the overheating problems water has been injected at the upper part of the water jacket. In U.S. Pat. No. 6,293,121 atomizer nozzles are used to maximize the water surface. Both methods have limited success and longevity, the heat of the exhaust and corrosiveness of the seawater combine to close the water orifices.  
     SUMMARY OF THE INVENTION  
      The present invention is directed to an exhaust diverter nozzle for atomizing cooling seawater in exhaust systems of marine engines run at low rpm (1600-2000 rpm). Atomization of the seawater enhances evaporation of the seawater which greatly enhances the cooling of the exhaust tubes which are frequently composed of a rubber (silicone) material which cannot withstand high heat. Silicone melts at 350° F. The exhaust diverter nozzle is comprised of a configured circular tube of sufficient diameter to be fitted within an exhaust hose. Exhaust hoses come in diameters of 3″-12″, varying according to the size and application of the marine engine. Exhaust hoses 5″ in diameter are commonly used in the Nordhavn 35 Coastal Pilot. The 5″ diameter exhaust diverter nozzle is comprised of a 5″ circular tube with an inlet and an outlet and a longitudinal length of 5″, a lip at the outlet, and two longitudinal diverters. The two longitudinal diverters are 2-5 mm thick and 2″ wide and are attached to the internal of the circular tube extending longitudinally from the inlet to the outlet. The diverters are mounted with their 2″ width at a right angle to the internal surface of the circular tube. The diverters are mounted parallel adjacent to each other at the lower part of the tube inlet. Each diverter travels longitudinally climbing each internal side while remaining at a right angle to the internal tube surface until reaching the tube outlet at the 90 position. At the tube outlet each diverter is on a horizontal plane. The outlet of the circular tube has a circumferential 45 degree lip extending at least ⅜″ inwards towards the axial center of the tube outlet.  
      The exhaust diverter nozzle is inserted within the rubber exhaust tube adjacent to the exhaust elbow outlet. The exhaust tube is often composed of two layers of silicone with a layer of fiberglass between them. The exhaust diverter nozzle is mounted with the diverters at the lower part of the tube inlet. At low engine rpm (1600-2000 rpm) seawater only trickles at the lower portion of the exhaust tube. The function the diverters is to direct part of the water towards the upper part of the tube outlet where the water hits the 45 lip and is directed inwards to form an atomized water column. The exhaust hits the atomized water column and the heat of the exhaust gas vaporizes the water into gas which produces a cooling effect similar to that of an evaporative cooler. The conversion of liquid to gas requires heat which is drawn from the environment. The exhaust gas temperature measured following the exhaust diverter nozzle measures 120 F when a marine diesel engine is run 1600-2000 rpm. Without the exhaust diverter nozzle the measured temperature is 250° F.  
      The composition of the exhaust diverter nozzle in a preferred embodiment is a metal alloy containing titanium which is highly resistant to heat and corrosion from seawater. Any soldering or welding materials should contain titanium. In another embodiment the exhaust diverter nozzle may be comprised of other materials, such as ceramics, which have the qualities of resistance to heat and seawater corrosion.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an inlet end view of the exhaust diverter nozzle;  
       FIG. 2  is a side view of the exhaust diverter nozzle;  
       FIG. 3  is a side view of an exhaust diverter nozzle connected to an exhaust tube with an exhaust diverter nozzle fitted internally; and  
       FIG. 4  is a side view of the invention with seawater flow. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIGS. 1-4  the exhaust diverter nozzle  1  has a tubular longitudinal body  2  with an external  3 , and internal  4 , an open inlet end  5  and an open outlet end  6 . The external diameter  3  of the tubular longitudinal body  2  should be sufficient to fit within a marine exhaust tube  31  as shown in  FIGS. 3 and 4 . The marine exhaust tubes  31  come in diameters of 3″-12″, 5″ being the most common, but vary according to use. In a preferred embodiment tubular longitudinal body  2  has a 5″ diameter with a minimum length of 5″. The open outlet end  6  of the tubular longitudinal body  2  has a 45° lip  7  extending inwards and away from the tubular longitudinal body  2 . The lip  7  must have a minimal width of ⅜″. In  FIGS. 1 and 2  extending inwards at a right angle from the internal surface  4  of the tubular longitudinal body  2  are left  8  and right  9  longitudinal diverters  8  and  9 . The diverters  8  and  9  are 24 mm wide and 2″ minimum in height. In  FIGS. 1, 2  and  3  the left  8  and right  9  diverters are adjacent and parallel to each other at the lower portion  10  of the inlet  5 . The left  8  and right  9  diverters extend longitudinally in the internal  4  of the longitudinal body  2 , each diverter  8  and  9  remaining 90° to the internal surface  4  as they climb upwards 90° as they reach the outlet end  6  of the tube  2 .  
      In  FIGS. 1, 2  and  3  the outlet end  6  extends inwards 45° to the long axis of the tubular longitudinal body  2  a minimum of ⅜″.  FIG. 3  shows a marine exhaust elbow  33  which functions by mixing sea water with exhaust gas.  FIG. 3  shows a common exhaust elbow  33  where the water channel  32  encircles the exhaust  34 . The seawater  32  mixes with the exhaust  34  where the exhaust tube  31  attaches to the exhaust elbow  33 . The exhaust diverter nozzle  1  is located within the interior of the exhaust tube  31  adjacent to the exhaust elbow  33 . A hose clamp  35  is attached external to the exhaust tube  2  which holds the exhaust diverter nozzle  1  in place. In  FIG. 4  at low engine rpm speeds (1600-2000 rpm) the seawater, due to the lack of volume of water flow, is mainly in the lower portion of the seawater channel  32 . The right and left diverters  8  and  9  direct the seawater  40  upwards towards the tube outlet  6  wherein the water  40  is uniformly distributed around the entire outlet  6 . The seawater  42  then strikes the 45° lip  7  which directs the seawater  42  inwards in a conical sheet  41  which atomizes the water  42 . The exhaust  34  then hits the atomized water  42  which vaporizes the water  42  resulting in evaporative cooling of the exhaust.  
      The sizes of the parts of the exhaust diverter nozzle vary proportionate to the varying diameters required to fit the variety of exhaust hose diameters.  
      The composition of the exhaust diverter nozzle  1  may be a variety of alloys or ceramic. The requirement of the composition is to withstand vibration, exhaust heat, and corrosion by the seawater. The material of choice contains titanium. The diverters may be constructed integral with the tubular longitudinal body  2  or attached to the tubular longitudinal body  2  by electro welding or soldering. The solder of choice contains titanium.