Abstract:
An outdoor microturbine engine assembly includes a microturbine engine supported by a base and enclosed by an enclosure. The base defines a reservoir for the collection of rain water and any oil that may leak from the engine into the reservoir. The oil will naturally float on the water in the reservoir. A drain pipe communicates with the bottom of the reservoir and drains water from the bottom of reservoir while maintaining the oil in the reservoir.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to an outdoor microturbine engine having a water and oil separator.  
       BACKGROUND  
       [0002]     Microturbine engines are used as relatively efficient sources of electricity and can be used in connection with the power grid or in a stand-alone mode. Because of their size and flexibility, microturbine engines are often used in field applications. Also, where a microturbine engine is used to supply electrical power to a building, it may be placed outside of building to maximize the use of the space within the building for other purposes.  
       SUMMARY  
       [0003]     The invention provides an outdoor microturbine assembly that includes a recuperated microturbine engine, a chassis supporting the engine and having side walls that define a reservoir, and a drain pipe for draining liquids from the reservoir. The drain pipe extends through an upper portion of one of the walls of the chassis at a drain level that is lower than the lowest portion of any of the side walls. The drain pipe angles downwardly to communicate with a bottom portion of the reservoir such that, when the combined volume of water and high-density liquids reaches the drain level, water from the bottom of the reservoir drains out of the drain pipe while the high-density liquids float on top of water and remain in the reservoir.  
         [0004]     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a perspective view of an outdoor microturbine engine.  
         [0006]      FIG. 2  is an exploded view of the outdoor microturbine engine.  
         [0007]      FIG. 3  is a cross-sectional view of a portion of the drain pipe in the microturbine base. 
     
    
       [0008]     Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0009]      FIG. 1  illustrates a microturbine engine  10  contained in an enclosure  15  suitable for outdoor use. The enclosure  15  includes a base or chassis  20 , enclosure walls  25  extending up from the base  20 , and a top  30  supported by the enclosure walls  25 . At least one access door  35  is provided in the enclosure walls  25  or may alternatively be in the top  30  of the enclosure  15  to provide access to the microturbine engine  10  from the top. When the access door  35  is closed, the enclosure  15  protects the engine  10  from the elements in a substantially weather resistant fashion. As used herein, the term “weather resistant” means that rain and other precipitation are prevented from reaching the engine  10  under normal conditions. For example, any vent openings in the enclosure  15  have hoods or shields that substantially prevent rain from entering the vent when the rain is falling vertically downward as in a typical rain shower, or when rain is falling at slight angles, as in a rain shower coupled with windy conditions.  
         [0010]     The base  20  includes side walls  40  that define a reservoir below the microturbine engine  10 . Inside the reservoir are a plurality of mounting points  45  for the microturbine engine  10  components. Any rain water or other precipitation that happens to enter the enclosure  15  (e.g., when the access doors  35  are left open or not shut properly) is collected in the reservoir.  
         [0011]     With reference to  FIG. 2 , the microturbine engine  10  includes a compressor  50 , a recuperator  55 , a combustor  60 , a power turbine  65 , and a generator  70 . The compressor  50  is used to compress air and deliver it to the recuperator  55 . The recuperator  55  is a heat exchanger that heats the compressed air before it reaches the combustor  60 . The combustor  60  is within one of the manifolds of the recuperator  55 . A fuel is mixed with the heated compressed air and the mixture is combusted in the combustor  60 . The expanding products of combustion from the combustor  60  cause a rotating element of the power turbine  65  to rotate. The rotating element drives the generator  70  to generate electricity. It will be appreciated that microturbine engines may include a single spool for driving both the compressor and the power turbine or dedicated spools for each of those elements. It should also be appreciated that the invention contemplates radial or axial flow compressors and power turbines.  
         [0012]     The products of combustion are still quite hot as they exit the power turbine  65 , and they are routed back through the recuperator  55  to preheat the incoming compressed air. The gases are typically still hot when they exit the recuperator  55 , and may be used for another purpose (e.g., the co-generation of hot water) before ultimately being exhausted to the atmosphere.  
         [0013]     As used herein, the term “high-density liquid” means any liquid having a specific gravity greater than that of water (i.e., greater than 1). The microturbine engine  10  uses lubricants, oils, coolants, and other substances that qualify as “high-density liquids” for the purposes of this invention. Because the specific gravity of high-density liquids is larger than the specific gravity of water, the high-density liquids will float on top of the water in the reservoir.  
         [0014]     With reference to  FIG. 3 , a drain pipe  75  extends through the top portion of one of the side walls  40  of the base  20 . The drain pipe  75  angles downwardly to the bottom of the reservoir beneath any layer of high-density liquids  77  that may have collect in the reservoir and float on the water  79  in the reservoir. A plate  80  is either integral with the pipe  75  or welded or otherwise affixed to the pipe  75 . The plate  80  is mounted to the outside of the base  20  with suitable fasteners or is welded as illustrated. The plate  80  preferably provides a substantially water-tight seal around the opening in the side wall  40  of the base  20  so that liquids cannot escape the reservoir except through the drain pipe  75 .  
         [0015]     A drain level  85  is defined as the horizontal plane extending through the bottom edge of the hole in the side wall  40  through which the drain pipe  75  extends. Thus, when the water and high-density liquids level in the reservoir reaches the drain level  85 , water  79  from the bottom of the reservoir will flow out of the drain pipe  75  and the high-density liquids  77  floating on top of the water will remain in the reservoir. A small amount of high-density liquid may enter the drain pipe  75  as the reservoir is initially filled, but that amount is considered negligible in comparison to the total volume of high-density liquid  77  in the reservoir. It should be noted that several drain pipes  75  may be used in the various side walls  40  of the base  20 . This is particularly useful if the reservoir is divided in a way that restrains or prevents communication between portions of the reservoir. In that case, one or more pipes  75  may be dedicated to each portion of the reservoir.  
         [0016]     The drain level  85  defines the volumetric capacity of the reservoir. That is to say that the reservoir will contain up to the volume of liquids necessary to overflow the drain level  85  and spill out of the drain pipe  75 . The total volume of high-density liquids in the engine is preferably lower than the volumetric capacity of the reservoir, such that if all high-density liquids used by the engine were to drain into the reservoir, the volume of high-density liquids alone would not reach the drain level  85 .  
         [0017]     The end of the drain pipe  75  that extends through the side wall  40  of the base  20  includes a tapered pipe thread adapted to communicate with a liquid pump  90  (shown schematically in phantom in  FIG. 1 ). The pump  90  may be attached to the drain pipe  75  and used to pump most of the liquids out of the reservoir.