Patent Publication Number: US-10766591-B2

Title: Cooling water drain system for a marine engine

Description:
FIELD OF THE INVENTION 
     The invention relates to a cooling water system for marine engines, and more particularly, to a system for draining cooling water from a marine engine cooling system. 
     BACKGROUND AND SUMMARY 
     Marine vessels often use “raw” water, for example, untreated sea water or lake water, for engine cooling. An open loop cooling system uses raw water as the sole coolant, drawing raw water into the system through an inlet formed on a drive unit or on the hull, circulating the raw water through the engine coolant passages, and discharging the raw water through the engine exhaust. A second type of system includes a closed loop part that circulates a coolant fluid (typically, a water-propylene glycol mixture) through engine coolant passages and through a water-to-water heat exchanger. A second part of the system draws raw water from outside the hull and directs it through the heat exchanger to remove heat from the coolant fluid. The raw water is then discharged through the engine exhaust system. 
     Both types of cooling system require occasional draining of the raw water from the cooling system. For example, raw water should be drained from the system when the ambient temperature is expected to fall below freezing to prevent damage to the engine (in the open loop system) or other coolant system components. Raw water is also drained so that the cooling system can be flushed with fresh water to remove salt residue, silt, and other undesirable substances. 
     Stern drives have engines mounted inside the hull. Draining cooling water from these arrangements includes opening a drain cock, removing a plug, or detaching a hose located at a low point of the cooling circuit and allowing the water to drain into the bilge under the force of gravity. Because it is located at a low point, the drain cock, plug, or hose is often difficult to reach. To solve this problem, U.S. Pat. No. 6,390,870 to Hughes, et al. proposes an open loop cooling system having a manifold located at a low point of the engine cooling system to which the various cooling hoses are connected. The manifold includes a drain tube. An elongated rod is mounted for movement that opens and closes the drain tube, the rod having a plug end that is removably inserted in the drain tube and a handle at an end accessible at a location above the manifold. 
     To drain the cooling system while the vessel is in the water, that is, when the raw water intake is submerged in the water, it is necessary to prevent siphoning of new raw water into the system as the draining raw water flows from the drain. This may be done by opening a vent in the water line to allow air in the line. Examples of vents in the art include passive vents, for example, float valve controlled vents and manually operated vents. 
     The invention provides an apparatus for draining a marine engine cooling system, including a raw water passageway having a raw water intake for drawing raw water into the raw water passageway, and including a conduit arranged to have a vertically high point and a vertically low point, a drain valve connected to the raw water passageway at the conduit vertically low point, a vent line connected to the raw water passageway at the conduit vertically high point and, a control handle located remote from the conduit vertically high point and the conduit vertically low point, the control handle being operatively connected to a vent valve connected to the vent line, wherein actuating movement of the control handle selectively opens and closes the vent valve. 
     According to the invention, the control handle is connected to the drain valve by a cable, and the actuating movement of the control handle that opens and closes the vent valve simultaneously opens and closes the drain valve. 
     According to an embodiment of the invention, the drain valve includes a hollow, cylindrical body having a drain inlet and a drain outlet, with a spool disposed in the hollow, cylindrical body and connected to the cable, the spool having a first position preventing flow between the drain inlet and the drain outlet and a second position connecting the drain inlet and the drain outlet. 
     According to another aspect of the invention, the vent valve is integrated in the control handle. The control handle of this embodiment comprises a tubular body having a vent port to which the vent line is connected and having an air relief opening, and comprising a valve member movably disposed in the tubular body having a closed position blocking flow between the vent port and the air relief opening and having an open position allowing flow between the vent port and the air relief opening. 
     Alternatively, the vent valve is located remote of the control handle and the control handle is connected to the vent valve by a cable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood by reference to the following detailed description read in conjunction with the figures, in which: 
         FIG. 1  is a schematic drawing of an open loop cooling system for a marine engine according to an embodiment of the invention; 
         FIG. 2  is a schematic drawing of a closed loop cooling system for a marine engine having an open loop heat exchanger according to another embodiment of the invention; 
         FIG. 3  is a drawing of a water drain valve according to the invention; 
         FIG. 4  is a drawing of a control handle having an integrated vent valve according to the invention; and, 
         FIG. 5  is a schematic drawing of an alternative embodiment of the control handle. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic drawing of an open loop cooling system for a marine engine that includes a water drain system according to an embodiment of the invention.  FIG. 1  illustrates a stern drive arrangement including an engine  10 , which is disposed in the vessel hull (not illustrated) and a drive unit  12  mounted on the stern (also not illustrated). The engine exhaust is carried by one or more exhaust conduits  14  to the drive unit  12 , which includes an internal conduit which directs the exhaust through the propeller hub  16  and into the wash behind the vessel. 
     The open loop cooling system includes a raw water intake port  20  on the drive unit  12 . Alternatively, a raw water intake may be provided on the vessel hull. Raw water is carried by an intake conduit  22  to the engine inlet port  24 . A pump  26  is disposed on the intake conduit  22  to circulate the water. The raw water circulates through cooling passages (not illustrated) formed in the engine  10  and exits through the outlet port  28 . The used raw water is carried by an outtake conduit  30  to the engine exhaust conduits  14 . The exhaust conduits  14  may be jacketed and the raw water may be first introduced into the jacket or jackets to cool the exhaust conduits, as well as the exhaust gas, before being directed into the engine exhaust flow. 
     A drain valve  40  is connected to the cooling system at a vertically low point of the system, that is, a location where gravity will cause the water to flow. The drain valve  40  may be connected to one or more of the cooling system conduits. As illustrated, the drain valve  40  is connected by a first drain conduit  42  to the outtake conduit  30 , by a second drain conduit  44  to the intake conduit  22  on the inlet side of the pump  26 , and by a third drain conduit  46  to the intake conduit  22  on an outlet side of the pump. The drain valve  40  includes at least one drain outlet  48 .  FIG. 1  (and  FIG. 2  which shows an alternative arrangement) is a schematic drawing; in a physical layout, the cooling system conduits  22 ,  24  and pump  26  may be arranged at physical low points to facilitate gravity-induced drainage. 
     The drain valve  40  is closed during normal use of the engine, that is, when the cooling system is operated, and will be opened when desired to drain the cooling system. When the drain valve  40  is closed, there is no flow through the drain valve or the drain conduits  42 ,  44 ,  46 . An exemplary drain valve  40  is described in connection with  FIG. 3 . 
     Still referring to  FIG. 1 , the drain valve  40  is operated by a control handle  50  located remote from the drain valve and connected to the drain valve by a cable  52 . The cable is preferably a wire rope cable capable of receiving and transmitting push and pull forces. Sliding movement of the handle  50  is transmitted by the cable to the drain valve  40  to selectively open or close the valve. The cable  52  is carried by a sheath  54  to constrain movement of the cable to the sliding movement. The control handle  50  has a handle  60  connected by a shaft  64  to the cable  52  to impart the sliding movement. Because the control handle  50  is connected by a cable to the drain valve  40 , the cable may be routed as convenient and the control handle may be conveniently located relative to the engine  10  for ready access. 
     The control handle  50  includes an anti-siphon vent valve  70 , described in greater detail in connection with  FIG. 4 . The vent valve  70  is opened and closed with the same action of the control handle  50  that opens and closes the drain valve  40 , so that both the drain valve and vent valve are open at the same time and both are closed at the same time. As shown in  FIG. 1 , the vent valve  70  is connected by a vent line  72  to the raw water intake conduit  22  at a vertically high point  78  of the intake conduit, that is, a point which is always above the waterline of the vessel. The intake conduit  22  may be routed to provide the high point  78 , which may be, but is not necessarily, the physically highest point of the intake conduit  22 . The vent valve  70  includes an air relief opening  76 . In the vent valve open position, the vent valve air relief opening  76  is in communication with the raw water intake conduit  22  by way of the vent line  72 , allowing air to flow into the vent line and intake conduit  22  and preventing a siphon effect in the water drain circuit. 
       FIG. 2  shows an alternative arrangement including a closed loop engine cooling system with a raw water heat exchanger  182 . In the arrangement of  FIG. 2 , the engine  110  has a closed loop cooling system including a pump  126  that circulates a coolant (typically a water-propylene glycol mixture) into a cooling inlet  124 , through the engine cooling passages (not illustrated), out a cooling outlet  128 , through a heat exchanger  182 , and back to the cooling inlet. The arrangement flows raw water through the heat exchanger  182  to cool the engine coolant. Raw water is drawn into the system through an intake  120  formed on the drive  112  (or alternatively, the vessel hull) and is carried by an intake conduit  122  to the heat exchanger  182 . A pump  180  pulls the raw water through the intake conduit  122  and directs the raw water through the heat exchanger  182  and through an outtake conduit  130  to the engine exhaust  114 . After use by the system, raw water is ejected through the engine exhaust  114  out of the propeller hub  116 . 
     The raw water system includes a drain valve  40  and control handle  50  according to the invention and as described in connection with  FIG. 1 . The drain valve  40  is connected to the raw water cooling system at a vertically low point of the system, that is, a location where gravity will cause the water to flow. The drain valve  40  may be connected to one or more of the cooling system conduits. As illustrated, the drain valve  40  is connected by a first drain conduit  42  to the outtake conduit  130 , by a second drain conduit  44  to the intake conduit  122  on the inlet side of the pump  180 , and by a third drain conduit  46  to the intake conduit  122  on an outlet side of the pump. The drain valve  40  includes at least one drain outlet  48 . 
     The drain valve  40  is operated by a control handle  50  located remote from the drain valve and connected to the drain valve by a cable  52 , preferably, a wire rope cable capable of receiving and transmitting push and pull forces. Sliding movement of the handle  50  is transmitted by the cable to the drain valve  40  to selectively open or close the valve. The cable  52  is carried by a sheath  54  to constrain movement of the cable to the sliding movement. The control handle  50  has a handle  60  connected by a shaft  64  to the cable  52  to impart the sliding movement. Because the control handle  50  is connected by a cable to the drain valve  40 , the cable may be routed as convenient and the control handle may be conveniently located relative to the engine  110  for ready access. 
     The control handle  50  includes an anti-siphon vent valve  70 , described in greater detail in connection with  FIG. 4 . The vent valve  70  is opened and closed with the same action of the control handle  50  that opens and closes the drain valve  40 , so that, both the drain valve and vent valve are open at the same time and both are closed at the same time. The vent valve  70  is connected by a vent line  72  to the raw water intake conduit  22  at a vertically high point  78  of the intake conduit, that is, a point which is always above the vessel waterline. 
     The intake conduit  22  may be routed to provide the high point  78 . The vent valve  70  includes an air relief opening  76 . In the open position, the vent valve relief opening  76  is in communication with the raw water intake  22  by way of the vent line  72 , allowing air to flow and preventing a siphon effect in the water drain circuit. 
       FIG. 3  is a schematic drawing of an exemplary embodiment of a drain valve  40  in accordance with the invention. The drain valve  40  is a sliding spool type valve and includes a hollow cylindrical body  242  that is closed at both ends by end walls  244 ,  246 . The drain valve body  242  includes inlet openings  250 ,  252 ,  254  for connecting the drain conduits  42 ,  44 ,  46  (see,  FIGS. 1 and 2 ) to the interior  256  of the drain valve body, and include exit openings  260 ,  262 ,  264 . A sliding spool  270  is disposed in the interior  256  of the drain valve  40  and includes three lands  272 ,  274 ,  276  that control drain water flow through the inlet openings  250 ,  252 ,  254  and define between them grooves or chambers that allow water flow. The lands  272 ,  274 ,  276  are shown in  FIG. 3  in a closed position, and may include O-rings or other appropriate devices to ensure sealing against the drain valve body  242 . The lands  272  and  274  define between them a chamber  280 , lands  274  and  276  define a chamber  282 , and the land  276  and the end wall  246  define a chamber  284 . The spool  270  is coupled to the control handle cable  52  in a convenient manner so that the spool may be caused to slide by movement of the control handle  50  transmitted by the cable. Sliding movement of the spool  270  in the valve body  242  in the direction to the left in  FIG. 3  causes chamber  280  to be open to inlet opening  250  and exit opening  260 , chamber  282  to be open to inlet opening  252  and exit opening  262 , and chamber  284  to be open to inlet opening  254  and exit opening  264 , which allows water to drain from the drain lines  42 ,  44 , and  46  through the drain valve  40 . 
       FIG. 4  is a schematic drawing of an exemplary embodiment of a control handle  50  in accordance with the invention. The control handle  50  includes a handle body  350  which is adapted to be mounted on or near the engine  10  in a location that is readily accessible to a user. A handle  60  for manually operating the control handle is carried on a shaft  62 . The shaft  62  is supported by end walls  352 ,  354  of the handle body  350  for sliding movement actuated manually by the handle  60 . The end of the shaft  62  opposite the handle  60  is coupled to the cable  52  so that sliding movement of the handle  60  and shaft  62  is imparted to the cable  52  and transmitted to the drain valve  40  as described above. 
     The control handle  50  illustrated in  FIG. 4  includes a vent valve  70  integrated in the handle body  350  and actuated by the handle  60  and shaft  62 . The vent valve  70  includes a spool  80  disposed in the handle body  350  and coupled to the shaft  62  for sliding movement in the handle body  350 . The spool  80  and the end wall  352  define between them a chamber  84 . The spool  80  has a closed position that blocks a vent port  82 , which may be formed as a nipple, that connects to the vent line  72 . The spool  80  has an open position, when moved relative to the handle body  350  to the left in  FIG. 4 , that connects the vent port  82  and the air relief opening  76  to the chamber  84 , which allows the free flow of air through the chamber  84  and to the vent line  72 . 
     The control handle  50  shown and described is operated manually by pushing or pulling the handle  60 . However, those skilled in the art will understand that a motor, for example, a solenoid, may be used in place of the handle  60  and operated by a switch at the vessel helm. 
       FIG. 5  is a schematic drawing of an alternative embodiment of the control handle  450 . 
     According to this embodiment, a vent valve  450  is a separate component (i.e., not integrated in the control handle as shown in  FIG. 4 ) and is located remote from the control handle  450 . Both the drain valve  40  and the vent valve  450  are actuated by cables  52 ,  452 , respectively, connected to the control handle  450 . The vent valve  450  of this embodiment may be located at any convenient place, for example, adjacent to the high points of the intake conduits (see,  FIG. 1  and  FIG. 2 ). 
     The foregoing description is meant to be illustrative and not limited to the literal terms described; other variations or substitutions may be made as will occur to those skilled in the art. For example, the drain valve and vent valve have been shown and described as sliding spool valves, but other valve arrangements are possible, including rotary spool valves, gate valves, and other valves that may be actuated by a linear movement of a cable.