Patent Publication Number: US-2006011152-A1

Title: Method and apparatus for cooling engines in buildings at oil well sites and the like

Description:
This application claims priority of Canadian Application No. 2,474,415, filed Jul. 15, 2004. The contents of which are hereby incorporated in their entireties by reference into this application.  
      This invention is in the field of cooling engines, and in particular for cooling stationary engines located inside a building at an oil well side or the like.  
     BACKGROUND  
      A typical oil and gas well site will often include an internal combustion engine to provide power for certain apparatuses present at the site such as a hydraulic pump which in turn powers a hydraulic motor, which will rotate a pump in the well. These internal combustion engines are typically multi-cylinder engines such as inline 6s, V-6s and V-8s and commonly automobile engines that have been modified for stationary use. These engines are typically housed within a protective building at the well site location, where the engines typically run at a relatively low, steady RPM for extended periods of time. The engines, being stationary in a closed-in space and operating for extended periods of time, suffer from overheating problems during warm weather when the ambient temperature of the air surrounding the engine is high and the cooling system of the engine is insufficient to cool the engines.  
      Internal combustions engines are relatively inefficient and tend to lose a lot of energy in the form of heat. This loss of energy in the form of heat necessitates the use of a cooling system for the internal combustion engine. Typically a cooling system for an internal combustion engine comprises a heat exchanger provided by a radiator located just forward of the internal combustion engine. Liquid coolant is circulated through the internal combustion engine and out into the radiator where it is cooled by the air drawn through the radiator by a fan. This cooled coolant then passes back into the engine where it circulates through the engine again absorbing heat to cool the engine.  
      For internal combustion engines that are mounted in moving vehicles, the radiator is usually moving in a relatively open space. Thus the air being drawn through the radiator is always changing, and as well the movement of the vehicle increases air flow through the radiator increasing its effectiveness. Stationary engines in enclosed spaces suffer from disadvantages usually not present in engines mounted in moving vehicles. The stationary internal combustion engines near well sites are typically protected by buildings. The buildings are typically vented to allow outside air to circulate through the building however the heat removed from the coolant by the radiator, and that generated by the engine itself, does not entirely dissipate and the temperature of the air within the building increases above the ambient outside temperature. On warm days the temperature inside these buildings can get quite high, reducing the effectiveness of the engine&#39;s cooling system and increasing the risk of overheating.  
      Such engines are generally protected such that they shut down when overheating is detected. Where the engine is operating a well pump, the pump shuts down, and production stops until the situation is detected and corrected. Often these well sites are only visited once a day and so considerable production can be lost. Where the production fluid pumped from the well comprises a considerable amount of sand, as is common in some areas, the sand can settle and make the pump difficult to restart, and possibly require that the well be flushed before the pump can be restarted.  
      In order to reduce the risk of over-heating, the thermostats on the stationary internal combustion engine are often removed in an effort to increase the effectiveness of the internal combustion engine&#39;s cooling system. Such removal is not typically very effective since the thermostats are generally running wide open in any event. In order to reduce the temperature of the ambient air around the radiator it is also known to remove the building&#39;s roof, or completely removing the buildings in the summer, so the stationary internal combustion engines are in the open. Removing the roof or building exposes the equipment inside to the elements, and is time consuming and involves considerable labor.  
      In very cold winter weather, in addition to shielding equipment from the elements, the protective building traps heat generated by the stationary engines, and beneficially maintains a warmer environment for the equipment, improving its operation.  
     SUMMARY OF THE INVENTION  
      It is an object of the present invention to provide a cooling apparatus for engines housed in buildings that overcomes problems in the prior art.  
      In a first embodiment the invention provides an apparatus for cooling an internal combustion engine located in a building, the engine including a liquid coolant circulating cooling system. The apparatus comprises an auxiliary heat exchanger operative to transfer heat from a liquid coolant flowing through the auxiliary heat exchanger to an air stream passing through the auxiliary heat exchanger. A supply conduit is adapted for operative connection to a pressurized portion of the cooling system at an input end thereof and is operatively connected to a supply port of the auxiliary heat exchanger at an output end thereof. A return conduit is adapted for operative connection to a suction portion of the cooling system at an output end thereof and is operatively connected to a return port of the auxiliary radiator at an output end thereof. A fan is operative to draw air through the auxiliary heat exchanger. The auxiliary heat exchanger, supply conduit, return conduit, and fan are configured such that the auxiliary heat exchanger can be located outside the building.  
      In a second embodiment the invention provides an enclosed engine apparatus with auxiliary cooling. The apparatus comprises an internal combustion engine located in a building, the engine including a liquid coolant circulating cooling system and an electrical system. An auxiliary heat exchanger is operative to transfer heat from a liquid coolant flowing through the auxiliary heat exchanger to an air stream passing through the auxiliary heat exchanger, and the auxiliary heat exchanger is located outside the building. A supply conduit is operatively connected at an input end thereof to the cooling system at a heater supply fitting on the engine and is operatively connected to a supply port of the auxiliary heat exchanger at an output end thereof. A return conduit is operatively connected at an output end thereof to the cooling system at a heater return fitting on the engine and is operatively connected to a return port of the auxiliary heat exchanger at an input end thereof. A fan is powered by the electrical system of the engine and is operative to draw air through the auxiliary heat exchanger.  
      In a third embodiment the invention provides a method of cooling an internal combustion engine located in a building, the engine including a liquid coolant circulating cooling system and an electrical system. The method comprises providing an auxiliary heat exchanger operative to transfer heat from a liquid coolant flowing through the auxiliary heat exchanger to an air stream passing through the auxiliary heat exchanger, and locating the auxiliary heat exchanger outside the building; connecting an input end of a supply conduit to the cooling system at a heater supply fitting on the engine and connecting an output end of the supply conduit to a supply port of the auxiliary heat exchanger; connecting an output end of a return conduit to the cooling system at a heater return fitting on the engine and connecting an input end of the return conduit to a return port of the auxiliary heat exchanger; and drawing air through the auxiliary heat exchanger with a fan powered by the electrical system of the engine.  
      The present invention provides an auxiliary cooling system that allows the stationary internal combustion engine to maintain all of the benefits of being housed within a building while at the same time reducing the problems that occur when an engine is operated in a warm confined space. A portion of the engine&#39;s coolant is routed to an auxiliary heat exchanger or radiator located outside the building. The coolant that is routed through the auxiliary heat exchanger passes through the auxiliary heat exchanger and is routed back into and through the internal combustion engine. Because these stationary internal combustion engines are typically slightly modified vehicle engines and the plumbing for a heater core is in place, it is economical and convenient to connect the auxiliary cooling system to the stationary internal combustion engine using the heater hose connections.  
      The auxiliary heat exchanger can be readily provided by an economically available conventional engine radiator of approximately the desired size, since precision in sizing is not contemplated to be critical. Further, many vehicle engines operate their conventional cooling fans with electric motors, and such electric powered fans are also readily available at an economical cost. The auxiliary cooling system of the invention can thus be readily provided at an economical cost, and provide added cooling that reduces the risk of over-heating and engine shut down or damage.  
      Because the auxiliary heat exchanger is located outside the building, the auxiliary heat exchanger does not suffer the disadvantages of the main radiator for the internal combustion engine. Unlike the main radiator or heat exchanger, which is located within a closed space, the auxiliary heat exchanger is out in the open which allows heat released into the surrounding air by the second heat exchanger to better dissipate.  
      In colder weather the auxiliary cooling system can be moved inside the building to function as a heater inside the building. 
    
    
     DESCRIPTION OF THE DRAWINGS:  
      While the invention is claimed in the concluding portions hereof, preferred embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagram where:  
       FIG. 1  is a schematic view of a stationary internal combustion engine system wherein a stationary internal combustion engine is housed within a protective building and is connected to an auxiliary cooling system of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS:  
       FIG. 1  schematically illustrates a stationary internal combustion engine system, incorporating an auxiliary cooling system  10  of the present invention. The stationary internal combustion engine system comprises a stationary internal combustion engine  15  located within a protective building  50  which serves to protect equipment including the engine  15  and typically other equipment. The illustrated engine  15  is connected to an auxiliary cooling system  10  to provide added cooling of the engine and reduce over-heating.  
      The engine  15  is a stationary internal combustion engine and is used to power a device, for example a hydraulic pump  17  that drives a rotary pump in an oil well, that is connected to the drive shaft of the engine  15 . The engine  15  has a cooling system comprising a heat exchanger in the form of a main radiator  20  connected to the intake  22  of a pump  24 . The pump output  26  is connected to a thermostat valve  28  which initially at start up is closed and directs all coolant to flow through circulation passages  19  defined in the engine block and then back to the pump intake  22 . As the engine temperature rises, the thermostat valve  28  opens such that a portion of the coolant from the pump output flows into the main radiator  20  at a radiator input  30  and then through the main radiator  20  to the pump intake  22 . Coolant passing through the main radiator  20  is mixed at the pump intake  22  with coolant flowing from the circulation passages  19 , thereby cooling the coolant.  
      The engines  15  used are typically commonly available and economical automobile engines which come in many varied sizes such that power requirements can be readily matched to engine size. Such engines come equipped with fittings  32 ,  34  that allow connection of the cooling system to a vehicle heater, typically by threading a connecting member into the fitting. The vehicle heater comprises core through which warm coolant from the engine passes, and a heater fan blowing air through the heater core into the vehicle. Although the location may vary, such fittings  32 ,  34  typically include a heater supply fitting  32  connected to the circulating passages  19  and a heater return fitting  34  connected to the pump intake  24  such that coolant is pumped through the heater core. In a typical stationary engine these fittings  32 ,  34  are simply blocked off by a threaded plug.  
      The engine  15  includes an electrical system operatively connected to a battery  36  to supply the electrical needs of the engine  15 .  
      The auxiliary cooling system  10  comprises an auxiliary heat exchanger, provided by auxiliary radiator  40 , that is located outside the building. Supply conduit  42  is connected to heater supply fitting  32  at an input end thereof and connected to a supply port  43  of the auxiliary radiator  40  at an output end thereof. Return conduit  44  is connected to the heater return fitting  34  at an output end thereof and connected to a return port  45  of the auxiliary radiator  40  at an input end thereof. The connection is substantially the same as a heater is connected in a vehicle engine. The connection thus conveniently requires no modification of the engine  15 . Coolant circulates through the auxiliary radiator  40 .  
      Typically the auxiliary cooling system  10  will also comprise a fan  46  that is operated by an electric motor  48  connected to the electrical system of the engine  15 , typically to the battery  36 . The fan  46  serves to increase the air flow passing through the auxiliary radiator  40 .  
      A portion of the coolant circulating under pressure from the pump  24  through the coolant circulation passages  19  will be routed out of the coolant circulation passages  19  through the heater supply conduit  42  to the auxiliary radiator  40  where heat is lost to the air passing through the auxiliary radiator in response to the fan  46 . The coolant then returns from the auxiliary radiator  40  to a suction portion of the cooling system at the pump intake  22  through return conduit  44  and heater return fitting  34 . Coolant will circulate through the main radiator, circulation passages  19 , and auxiliary radiator  40 . Thus heat is removed from the coolant through heat exchange with air at both the main radiator  20  and auxiliary radiator  40 , rather than only through heat exchange at the main radiator  20 . Thus added cooling of the engine coolant is provided, reducing the risk that the engine  15  will over-heat and either cause the engine  15  to shut down, or cause damage to the engine  15 .  
      While the illustrated embodiment shows that convenient connection of the auxiliary radiator  40  to the cooling system is provided by connecting to the heater fittings  32 ,  34 , it will be readily apparent to those skilled in the art that many of the various connections illustrated in  FIG. 1  could be located in a number of places and the invention will still operate.  
      Since the auxiliary cooling system  10  is only needed when the outside temperature is warm, in winter the auxiliary radiator  40  can be moved inside the building  50 . The supply and return conduits  42 ,  44  can be made long enough to locate the auxiliary radiator outside the building  50  in warm weather, and also allow the auxiliary radiator  40  to be moved to a location inside the building  50  away from the engine  15  to serve as a heater for a remote part of the building when the temperature outside the building is cold. Such a winter configuration is schematically illustrated in phantom lines in  FIG. 1  by auxiliary radiator  40 A, fan  46 A, supply conduit  42 A and return conduit  44 A.  
      The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.