Abstract:
A siphon inhibiting valve is provided for a marine engine cooling system. The purpose of the valve is to prevent the draining of the pump and outboard drive unit from creating a siphon effect that draws water from portions of the cooling system where heat producing components exists. The valve also allows intentional draining of the system when the vessel operator desires to accomplish this function. The valve incorporates a ball that is captivated within a cavity. If the ball is lighter than water, its buoyancy assists in the operation of the valve.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a marine engine cooling system and, more particularly, to a cooling system that is provided with a siphon inhibiting device to alleviate problems in marine engine cooling systems that can possibly result due to heated water reversing its normal flow direction when the engine is off. 
     2. Description of the Prior Art 
     Those skilled in the art of marine propulsion systems are aware of many different types of engine cooling systems. Typically, a water pump is used to draw water from the body of water in which the marine propulsion system is operated. The water is then conducted through a series of passages and into thermal communication with various heat producing components, such as the engine and its exhaust manifolds. After being used to remove heat from the heat producing components, the water is then typically combined with an exhaust stream from the engine and conducted overboard back into the body of water from which it was drawn. 
     U.S. Pat. No. 5,980,342, which issued to Logan et al on Nov. 9, 1999, discloses a flushing system for a marine propulsion engine. The flushing system provides a pair of check valves that are used in combination with each other. One of the check valves is attached to a hose located between the circulating pump and the thermostat housing of the engine. The other check valve is attached to a hose through which fresh water is provided. Both check valves prevent flow of water through them unless they are associated together in locking attachment. The check valve attached to the circulating pump hose of the engine directs a stream of water from the hose toward the circulating pump so that water can then flow through the circulating pump, the engine pump, the heads, the intake manifold, and the exhaust system of the engine to remove seawater residue from the internal passages and surfaces of the engine. It is not required that the engine be operated during the flushing operation. 
     U.S. Pat. No. 5,334,063, which issued to Inoue et al on Aug. 2, 1994, describes a cooling system for a marine propulsion engine. A number of embodiments of cooling systems for marine propulsion units are disclosed which have water cooled internal combustion engines in which the cooling jacket of the engine is at least partially positioned below the level of the water in which the water craft is operating. The described embodiments all permit draining of the engine cooling jacket when it is not being run. In some embodiments, the drain valve also controls the communication of the coolant from the body of water in which the water is operating with the engine cooling jacket. Various types of pumping arrangements are disclosed for pumping the bilge and automatic valve operation is also disclosed. 
     U.S. Pat. No. 6,004,175, which issued to McCoy on Dec. 21, 1999, discloses a flush valve which uses only one moving component. A ball is used to seal either a first or second inlet when the other inlet is used to cause water to flow through the valve. The valve allows fresh water to be introduced into a second inlet in order to remove residual and debris from the cooling system of the marine propulsion engine. When fresh water is introduced into a second inlet, the ball seals the first inlet and causes the fresh water to flow through the engine cooling system. When in normal use, water flows through the first inlet and seals the second inlet by causing the ball to move against a ball seat at the second inlet. Optionally, a stationary sealing device can be provided within the second inlet and a bypass channel can be provided to allow water to flow past the ball when the ball is moved against the ball seat at the first inlet. This minimal flow of water is provided to allow lubrication for the seawater pump impeller if the seawater pump is operated during the flushing operation in contradiction to recommended procedure. 
     U.S. Pat. No. 6,135,064, which issued to Logan et al on Oct. 24, 2000, discloses an improved drain system. The engine cooling system is provided with a manifold that is located below the lowest point of the cooling system of the engine. The manifold is connected to the cooling system of the engine, a water pump, a circulation pump, the exhaust manifolds of the engine, and a drain conduit through which all of the water can be drained from the engine. 
     The patents described above are hereby expressly incorporated by reference in the description of the present invention. 
     In certain types of marine propulsion systems, water can drain and thereby create a siphon effect that draws water from other components of the cooling system. When the engine is turned off, cooling water in the outboard drive drains downward to the water line. This draining initiates a siphon effect which, in turn, draws cooling water from the heated engine in a backwards direction through the cooling circuit. The heated water from the engine then enters and remains in the fuel/water heat exchanger which, in most cases, is a coaxial heat exchanging device. The heated water in this fuel/water heat exchanger causes the liquid fuel to increase in temperature and, in certain cases, vaporize. When the operator of a marine vessel then tries to restart the engine, this partially vaporized fuel in the fuel/water heat exchanger is difficult to displace with the typical electric fuel pump that is normally used. As a result, vapor lock can be experienced. 
     It would therefore be significantly beneficial if a means could be provided that prevents the siphon effect from draining the water from the cooling system soon after the pump is deactivated. It would be further beneficial if the siphon inhibiting means could also allow later draining of the cooling system. 
     SUMMARY OF THE INVENTION 
     A marine cooling system made in accordance with the present invention comprises a pump, a heat producing component, and a conduit connected between the pump and the heat producing component. In a marine propulsion system, the heat producing component can be the engine itself or associated devices, such as the exhaust manifolds and the exhaust elbows. 
     A preferred embodiment of the present invention also comprises a valve connected in fluid communication with the conduit between the pump and the heat producing component. A ball or poppet is disposed within a cavity of the valve, with the valve having a first port and a second port. In certain embodiments of the present invention, a poppet valve can be used instead of the ball. Throughout the description of the present invention it should be understood that the use of the term “ball” should be understood to describe the use of either a ball or a poppet valve. The first and second ports of the valve allow water to flow into and out of the valve during operation of the engine and during draining. The valve is configured to receive a stream of water into the first port from the pump and then pass the stream of water serially through the cavity and the second port to the heat producing component. The present invention further comprises a seal which is responsive to movement of the ball within the cavity and located between the first port and the cavity in order to inhibit water flow through the cavity toward the pump. The valve is positioned to dispose the first port above the second port when associated within a cooling system of a marine engine. 
     In a particularly preferred embodiment of the present invention, the ball is less dense than water and, as a result, floats on the water which is within the cavity of the valve. The seal is responsive to an upward movement of the ball within the cavity and, in a particularly preferred embodiment of the present invention, the seal is a ball seat which is shaped to receive the ball in sealing contact in response to movement of the ball against the ball seat. When water exists within the cavity of the valve, the water causes the ball to rise because the ball is less dense than the water. As the ball rises, it moves into contact with the ball seat and provides a seal. Also, flow of water upward within the cavity toward the first port from the second port, will also cause movement of the ball in an upward direct toward the ball seat. 
     In one embodiment of the present invention, the valve comprises a first portion and a second portion that are attached together to define the cavity which captivates the ball. In certain embodiments of the present invention, a ball rest is formed in the cavity proximate the second port in order to support the ball. The ball rest permits water to flow around the ball and through the second port when the ball is located on the ball rest at the bottom of the cavity. 
     The cooling system of the present invention can further comprise an engine having a plurality of cooling passages, with the valve being connected in fluid communication between the pump and the cooling passages. It can also comprise a thermostat housing connected in thermal communication with the valve and with the pump. Similarly, a fuel cooler and an exhaust manifold can be incorporated as part of the cooling system, with the valve being connected in fluid communication between the pump and both the fuel cooler and the exhaust manifold. 
     Although not a requirement in all embodiments of the present invention, it is preferable to locate the valve in the cooling system conduit between the pump and other components of the cooling system. Since the purpose of the valve of the present invention is to prevent, or at least inhibit, siphoning of water back through the pump, locating the valve closer to the pump than the heat producing components will facilitate its operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
     FIG. 1 is an exploded view of a marine engine cooling system; 
     FIG. 2 illustrates a prior art siphon inhibiting valve; 
     FIG. 3 and 4 show section views of the present invention under two states of operation; and 
     FIG. 5 is a section view of FIG.  4 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Throughout the description of the preferred embodiment of the present invention, like components will be identified by like reference numerals. 
     FIG. 1 is an exploded view showing the components of a marine engine cooling system. In the exploded view, various water paths are represented by various series of aligned arrows. These individual flow paths will be identified by specific reference numerals in the following description. 
     A pump  10  draws water from an intake  12  along a flow path  14 . The water intake  12  is disposed below the surface of a body of water in which the marine propulsion system is operating. Whether the body of water is a lake or sea, the water is drawn along flow path  14  by the pump  10  and induced to flow under pressure along flow path  18  and into the cooling passages of the cooling system. As an example, the power steering cooler  19 , the fuel cooler  20 , and an engine oil cooler  22  are shown connected in fluid communication with the conduits that conduct the flow path  18  toward a thermostat housing and cover assembly  30 . From the thermostat housing  30 , the cooling water is conducted along flow path  32  to an engine water circulating pump  36 . From the engine water circulating pump  36 , water is directed along two generally parallel flow paths,  41  and  42 , into the engine  50  after passing through the cooling passages within the structure of the engine  50 , the cooling water flows, along flow path  52 , back to an inlet of the thermostat housing  30 . From the thermostat housing  30 , water flows in two parallel flow paths,  61  and  62 , to the water jackets of the exhaust manifolds,  71  and  72 . After passing through the water jackets of the manifolds,  71  and  72 , the cooling water then flows into the exhaust elbows,  77  and  78 , along flow paths  81  and  82 . From there, the water is ejected with the exhaust gases as represented by flow paths  91  and  92 . 
     When the engine  50  is turned off and the pump  10  becomes inactive, water can drain from the pump  10 , in conduit  94 , in a direction opposite to flow path  14 . As this water in conduit  94  drains back into the body of water from which it was originally drawn, it can create a siphon effect which draws water from conduit  96  in a direction opposite to flow path  18 . As a result of this siphon effect, water can be drawn from various portions of the cooling system and away from certain heat producing components, such as the engine  50  and exhaust manifolds,  71  and  72 . This prevents the water from remaining in its intended locations to remove additional heat from the heat producing components. As described above in greater detail, the siphon effect can draw heated water back into the fuel/water heat exchanger and result in vaporization of the fuel in the heat exchanger. It should be understood that after the engine  50  is turned off, heat continues to emanate from the engine and be conducted into other various other components, particularly fuel containing and conducting components. As a result, these components experience a significant temperature rise after the engine is turned off. This temperature rise can create vapor lock problems when the operator of the marine vessel attempts to restart the engine. These vapor lock problems can be prevented if the cooling water remains within the cooling system in thermal communication with the heat producing components. 
     A siphon inhibiting device  100  is provided in series between the pump  10  and the heat producing components. The purpose of the siphon inhibiting device  100  is to prevent the flow of water within conduit  96 , in a direction opposite flow path  18 , resulting from a siphon effect that is initiated by water draining from the pump  10  back into the body of water in a direction opposite to the flow path  14 . 
     FIG. 2 shows a siphon inhibiting valve that is known to those skilled in the art and available in commercial quantities. The valve body  110  is provided with an inlet port  112  and an outlet port  114 . When the pump  10  is operating, water flows in the direction represented by arrow W in FIG. 2, enters the inlet port  112 , flows through the internal chamber  120  of the valve body  110 , and exits from the valve through the outlet port  114 . A spring  124  provides a force against a plunger  130  which seals a passage when the head  134  of the plunger  130  moves into sealing relation within a narrowed section  136  of the passage. Water pressure from the pump  10 , causes the flow W against the head  134  of the plunger  130  and, as a result, provides sufficient force against the plunger  130  to compress the spring  124  and allow water to flow downward in FIG. 2 serially through the inlet port  112 , the internal cavity  120 , and the outlet port  114 . When the pump  10  is deactivated as a result of the engine  50  being turned off, spring  124  moves the plunger  130  upward to prevent reverse flow in an upward direction in FIG. 2, opposite to the direction represented by arrows W. This prevents water from being drawn through conduit  96  in a direction opposite to the flow path  18  illustrated in FIG.  1 . Several disadvantages are inherent in the design shown in FIG.  2 . First, the force provided by spring  124  must be overcome by a downward force in the direction of arrow W against the head portion  134  of plunger  130 . This results in a pressure drop through the valve which, in turn, causes a measurable loss of flow through the cooling system compared to the flow that could otherwise by pumped by the pump  10 . Another deleterious result of the design shown in FIG. 2 is that water will be trapped on the inlet side of the head portion  134  when the operator wishes to drain the cooling system. Therefore, water will remain in certain conduits on the inlet side of the valve, upstream from the head portion  134  of plunger  130 . As a result, the draining procedure will be incomplete and some water will remain in the cooling system. This incomplete draining procedure can result in significant damage in the event that ambient temperatures decrease to below the freezing point of the cooling water. In addition, if the operator of the marine vessel attempts to operate the engine while a blockage exists within the cooling system, such as frozen cooling water, this blockage will prevent appropriate cooling of the engine and may cause damage. 
     With continued reference to FIGS. 1 and 2, it will be significantly beneficial if a siphon inhibiting valve  100  could be provided without the inherent disadvantages of the valve shown in FIG.  2 . 
     FIG. 3 shows a section view of a siphon inhibiting valve  100  made in accordance with the principles of the present invention. The valve  100 , as described above in conjunction with FIG. 1, is intended to be connected in fluid communication with a conduit  96  that is, in turn, connected between the pump  10  and a heat producing component, such as the engine  50  or the exhaust manifolds,  71  and  72 . A ball  200  is disposed within a cavity  204  of the valve  100 . The valve has a first port  211  and a second port  212 . The valve is configured to receive a stream of water into the first port  211  from the pump  10 , as described above in conjunction with FIG. 1, and past the stream of water serially through the cavity  204  and the second port  212  on its way to a heat producing component, such as the engine  50  or exhaust manifolds,  71  and  72 . A seal, such as the ball seat  220  is responsive to movement of the ball  200  within the cavity  204 . The seal is located between the first port  211  and the cavity  204  for the purpose of inhibiting water flow through the cavity  204  and through the first port  211  on its way back to the pump  10 . In operation, the valve  100  is positioned in the cooling system to dispose the first port  211  above the second port  212 . 
     In a particularly preferred embodiment of the present invention, the ball  200  is less dense than water and the seal, which comprises the ball seat  220 , is responsive to the upward movement of the ball  200  within the cavity  204 . In other words, when the ball  200  moves into contact with the ball seat  220 , it blocks passage through the valve  100 . 
     The valve  100  can comprise a first portion  231  and a second portion  232  which can be combined together, as shown in FIG. 3, to define the cavity  204  in which the ball  200  is captivated. 
     FIG. 3 shows the position of the ball  200 , relative to the cavity  204  and relative to the second port  212 , when water is flowing under the influence of the pump  10  in the direction represented by arrows W. When in this position, water can flow around the ball  200  with relatively little restriction. The resulting small pressure drop is not significant and does not represent an appreciable decrease in the efficiency of the cooling system. 
     FIG. 4 shows the valve  100  when the ball  200  is moved upward within the cavity  204  and against the ball seat  220 . The ball  200  will assume this position under two different circumstances. First, if water attempts to flow upward through the valve  100 , in the direction from the second port  212  towards the first port  211 , the flow of water will carry the ball  200  upward and into contact with the ball seat  220 . This will occur even if the ball is more dense than water. This movement will create a seal to prevent further movement of water in that same direction. Another circumstance that will cause the ball  200  to assume the position shown in FIG. 4 is the presence of non flowing water within the cavity  204 . Since, in a preferred embodiment of the present invention, the ball  200  is less dense than water, it will float on the water within the cavity  204  and be moved into position against the ball seat  220 . This position, as described above, will block further movement of water through the valve  100  in an upward direction from the second port  212  toward the first port  211 . 
     With continued reference to FIG. 4, it should be noted that a ball rest  230  is formed in the cavity  204  proximate the second port  212  for the purpose of supporting the ball  200  when the ball moves to the position illustrated in FIG.  3 . The ball rest  230  provides a plurality of ribs  234  as illustrated in FIG. 5 which is a section view of FIG. 4, as shown. The ribs  234  support the ball  200  above the non-ribbed portion of the surface  240  surrounding the opening leading to the second port  212 . As a result, water can freely flow around the ball  200 , and between the ribs  234 , when water is flowing in the direction represented by arrows W in FIG.  3 . 
     With reference to FIGS. 1,  3 ,  4 , and  5 , it can be seen that the present invention provides a means for preventing a siphon effect from drawing water through conduit  96  in a direction opposite to flow path  18 . As described above, this siphon effect can be created when water drains from the conduit  94  in a direction opposite to the flow path  14 . The valve  100  of the present invention prevents this continuing siphon effect that can lead to significant difficulty in starting the engine  50  because of vapor lock, as described in detail above. It can also be seen that the valve  100  of the present invention performs this function in a way that does not preclude the easy draining of the water cooling system at a later time. When the operator intentionally opens drain valves to induce draining of the cooling system, water flows away from the second port  212  and out of the cavity  204 . As a result, support for the ball  200  is removed and, in addition, forces on the ball  200  in a downward direction exceeds those in a upward direction. As a result, the ball  200  falls away from the ball seat  220  and rests on the ball rest which comprises the ribs  234 . This allows a complete draining of the system, including the portion of the cooling system comprising conduit  96  and the power steering cooler  19 , if provided in this system. As a result, the valve  100  of the present invention provides the beneficial affect of preventing the siphoning of water out of the cooling system while not adversely affecting the easy draining of the system when the watercraft operator desires to do so. 
     Although the present invention has been described in considerable detail and illustrated to show a preferred embodiment, it should be understood that alternative embodiments are also within its scope.