Abstract:
A gas compression system includes a compressor operable to discharge a mixed flow of gas and lubricant, a separator tank including an opening having a first face, and a separator element including a disk portion having a second face and a third face. The separator element is positioned at least partially within the opening and is operable to separate at least a portion of the lubricant from the mixed flow of gas and lubricant. A lid is coupled to the separator tank and includes a fourth face. A one-piece seal ring is coupled to the disk and is compressed between the lid, the disk, and the separator tank to define a first airtight seal between the first face and the second face and a second airtight seal between the third face and the fourth face.

Description:
BACKGROUND 
       [0001]    The present invention relates to seals for separator elements, and more particularly to formed seals for use in air-oil separators. 
         [0002]    Some air compressor systems use oil to lubricate the compressor, remove heat produced during the compression process, and to provide better seals between the compressor elements to improve compressor efficiency. One example of such a compressor system employs one or more oil-flooded screw compressors. 
         [0003]    Operation of oil-flooded compressors produces compressed air that is mixed with oil. It is necessary to separate the oil from the air before the air can be used. Typically, the oil is separated and returned to the compressor for reuse. In some systems, the oil is filtered, or cooled before it is returned to the compressor. 
       SUMMARY 
       [0004]    In one construction, the invention provides a gas compression system that includes a compressor operable to discharge a mixed flow of gas and lubricant, a separator tank including an opening having a first face, and a separator element including a disk portion having a second face and a third face. The separator element is positioned at least partially within the opening and is operable to separate at least a portion of the lubricant from the mixed flow of gas and lubricant. A lid is coupled to the separator tank and includes a fourth face. A one-piece seal ring is coupled to the disk and is compressed between the lid, the disk, and the separator tank to define a first airtight seal between the first face and the second face and a second airtight seal between the third face and the fourth face. 
         [0005]    In another construction, the invention provides a gas compression system that includes a compressor housing including a gas inlet, a lubricant inlet, and an outlet and a compressor element positioned at least partially within the compressor housing and operable to receive a flow of gas from the gas inlet and a flow of lubricant from the lubricant inlet and discharge a mixed flow of gas and lubricant from the outlet. A separator tank includes an opening having a first face and an inlet in fluid communication with the outlet to receive the mixed flow of gas and lubricant. A separator element includes a disk portion having a second face and a third face. The separator element is positioned at least partially within the opening such that the second face is in a facing relationship with the first face. The separator element is operable to separate at least a portion of the lubricant from the mixed flow of gas and lubricant. A lid includes a fourth face. The lid is coupled to the separator tank such that the fourth face is in a facing relationship with the third face. A one-piece seal ring is coupled to the disk and is compressed between the lid, the disk, and the separator tank to define a first airtight seal between the lid and the disk and a second airtight seal between the disk and the separator tank. 
         [0006]    In yet another construction, the invention provides a separator element for use in a gas compression system to separate at least a portion of a lubricant from a mixed flow of lubricant and a gas, the separator element configured to be positioned within a separator tank having a lid. The separator element includes a housing, a screen supported by the housing and arranged in a substantially cylindrical shape and including a plurality of apertures, and a filtering material disposed in a hollow cylindrical space within the screen and supported by the housing. A disk portion is formed as part of the housing and a one piece seal member is coupled to the disc portion. The seal member has a U-shaped cross section that defines a first leg portion and a second leg portion. The first leg portion is configured to define an airtight seal between the disk portion and the lid and the second leg portion is configured to define an airtight seal between the disk portion and the separator tank. 
         [0007]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a gas compression system including a separator; 
           [0009]      FIG. 2  is a section view of the separator of the gas compression system of  FIG. 1 ; 
           [0010]      FIG. 3  is a perspective view of a separator element suitable for use in the separator of  FIG. 2 ; 
           [0011]      FIG. 4  is a perspective view of a seal ring suitable for use with the separator of  FIG. 2 ; 
           [0012]      FIG. 5  is a section view of the seal ring of  FIG. 4  taken along line  5 - 5  of  FIG. 4 ; 
           [0013]      FIG. 6  is a section view of a portion of the separator of  FIG. 2  illustrating the seal ring; 
           [0014]      FIG. 7  is a section view of a portion of another separator suitable for use in the gas compression system of  FIG. 1  illustrating the seal ring; and 
           [0015]      FIG. 8  is a perspective view of a portion of the seal ring including a metallic grounding element. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
         [0017]      FIG. 1  illustrates a gas compression system  10  that operates to compress a gas such as air. The system includes a prime mover  15  that drives a compressor  20 , an oil separator  25 , a cooler  30 , and an oil filter  35 . In preferred constructions, a motor or engine is employed as the prime mover  15  with other devices also suitable for use as a prime mover  15 . 
         [0018]    The compressor  20  draws in air (or another gas) through an inlet  40  that typically includes an air filter and discharges the air from a compressor outlet  45  at a higher pressure. In the illustrated construction, an oil-flooded compressor  20  such as an oil-flooded screw compressor that includes two or more rotating screw elements  50  is employed. Oil is provided to the compressor  20  to improve the seal between the rotating elements  50 , to lubricate the rotating elements  50 , and to remove heat produced during the compression process. The oil mixes with the air and is discharged as an air-oil mixture from the compressor outlet  45 . 
         [0019]    The outlet  45  directs the air-oil mixture to the separator  25  where the oil is separated from the air. The air exits the separator  25  via a separator outlet  55  and flows to the cooler  30  and then to a point of use or to other treatment members (e.g., chillers, dryers, filters, etc.). The oil exits the separator  25  and flows through the filter  35  and may flow through an optional oil cooler  30  before being redirected to the compressor  20  for reuse. 
         [0020]    While the description describes a compression system  10  for compressing air and a separator  25  that separates air and oil, it should be understood that other gases could be compressed by the compressor  20 . For example, in one arrangement, a refrigerant compressor is used to compress a refrigerant. In addition, while oil is used in the described compressor  20 , other lubricants could also be employed and will function in the described device. Thus, while the device is described as using air and oil, other fluids could be employed. 
         [0021]    With reference to  FIG. 2 , the separator  25  includes a tank  60  that includes a side surface  63  that is generally cylindrical, a domed bottom portion  65 , and a flange  70  formed around a top opening  75 . The flange  70  includes a top surface  80  or face that is substantially planar. An inlet  85  is formed in the cylindrical side portion  63  of the tank  60  and is arranged to induce a cyclonic flow pattern that aids in the separation of the oil from the air-oil mixture as will be described. 
         [0022]    The separator  25  also includes a funnel member  90  and a lid  95  that selectively engages the flange  70  to enclose and substantially seal the interior of the tank  60 . The funnel member  90  is fixedly attached to the interior of the tank  60  to divide the tank  60  into a lower portion  100  and an upper portion  105 . The funnel member  90  is frustoconical with a small diameter portion facing downward. The air-oil inlet  85  is positioned in the lower portion  100  such that the air-oil mixture is admitted into the tank  60  beneath the funnel member  90 . The funnel member  90  includes one or more apertures  110  that allow the air-oil mixture to flow upward from the lower portion  100  to the upper portion  105 . The funnel member  90  also includes a central aperture  115  at the lower most point that provides a flow path for oil to pass from the upper portion  105  to the lower portion  100  where it collects in the domed portion  65 . It should be noted that the means employed to separate the oil and the air is not critical to the function of the invention as the invention is applicable to many different single stage and multi-stage separator arrangements. 
         [0023]    The lid  95  includes a bottom surface  120  or face that is substantially planar, an outlet aperture formed near the center of the lid  95  and a plurality of bolt apertures  125  positioned on the circumference of a bolt circle. Bolts  130  pass through each aperture  125  and engage the flange  70  of the tank  60  to attach the lid  95  to the tank  60  such that a bottom surface  120  of the lid  95  is in a facing relationship with the top surface  80  of the flange  70 . A separator element  140  sealingly engages the lid  95  and the flange  70  to separate the upper space  105  into a filtered space  145  and an unfiltered space  150 . The air-oil mixture must pass from the unfiltered space  150 , through the separator element  140  to the filtered space  145  in order to exit the separator  25 . The separator element  140  operates to separate a desired portion of the oil from the air-oil mixture such that the fluid that exits via the outlet  55  is substantially oil free air. The separated oil eventually drains from the separator element  140 , onto the funnel  90  and down to the domed portion  65  of the tank  60 . A drain  155  is provided on the bottom of the tank  60  to draw the oil back into the system  10  for reuse or for other uses as may be desired. 
         [0024]    With reference to  FIGS. 2 and 3 , the separator element  140  includes a housing  160  that supports a filter material  165 . In the illustrated construction, the housing  160  includes a cylindrical side surface  170 , a top  175 , and a bottom  180 . The cylindrical side surface  170  is perforated to provide for flow through the element  140 . In some constructions, the housing  160  provides a frame work and a screen is attached to that frame work to define the cylindrical side surface  170 . The filter material  165  is supported adjacent the cylindrical surface  170  and is configured to separate oil from air as the air-oil mixture flows through the material  165 . 
         [0025]    The bottom  180  of the housing  160  supports the filter material  165  and sealingly engages the side surface  170  to assure that little or no flow passes through the bottom  180  or bypasses the filter material  165  via the bottom  180 . In preferred constructions, the bottom  180  is fixedly attached to or formed as part of the side surface  170 . However, in some constructions, the bottom  180  is a separate piece positioned adjacent the side surface  170 . In the illustrated construction, the bottom  180  is not planar and is formed to direct oil that may collect on the bottom  180  toward the center of the bottom  180  or toward the outer diameter of the bottom  180 . In some constructions, a small aperture is formed in the center of the bottom  180  to drain any oil that might collect during operation. The bottom  180  also cooperates with the side surface  170  to sandwich a portion of the filter material  165  to inhibit movement of the filter material  165  inward during operation. 
         [0026]    The top  175  includes a cover portion  185 , an inner lip  190 , and a disk  195 . In preferred constructions, the top  175  is fixedly attached to or formed as part of the side surface  170 . However, in some constructions, the top  175  is a separate piece positioned adjacent the side surface  170 . The cover portion  185  is substantially planar and is positioned above the filter material  165 . The inner lip  190  extends downward from the cover portion  185  and cooperates with the side surface  170  to sandwich a portion of the filter material  165  to inhibit movement of the filter material  165  inward during operation. The disk  195  is a substantially planar annular portion that includes a top surface  200  or face and a bottom surface  205  or face that define a thickness. The top surface  200  and bottom surface  205  extend radially outward to a predetermined outer diameter. The disk  195  is sized to fit between the flange  70  and the lid  95  such that when the lid  95  is bolted to the flange  70 , the disk  195  is sandwiched therebetween to support the separator element  140  as illustrated in  FIG. 2 . 
         [0027]    As illustrated in  FIGS. 6 and 7 , a seal ring  210  is positioned around a portion of the disk  195  at the outer diameter. The seal ring  210  is sandwiched between the lid  95  and the flange  70  to improve the seal between these components. In the construction illustrated in  FIG. 6 , the flange  70  includes a step  215 , or counterbore, that results in a gap  220  between the flange  70  and the lid  95  when the lid  95  is attached to the flange  70 . The gap  220  is sized to provide the desired compression or preload of the seal ring  210  as will be discussed below. It should be understood that other constructions may form the step in the lid  95  or may be formed in both the lid  95  and the flange  70  to provide the desired gap  220 . 
         [0028]      FIG. 7  illustrates another arrangement in which the flange  70  and the lid  95  include flat parallel surfaces and a spacer  225  is positioned therebetween to define the desired gap  220 . In this construction, the spacer  225  is sized to produce a gap  220  of the desired size to provide the desired compression or preload of the seal ring  210 . Other arrangements could also be employed to establish the desired gap  220  without effecting operation of the seal ring  210 . 
         [0029]    As illustrated in  FIG. 4 , the seal ring  210  is a continuous ring that is formed from a resilient material. The resilient material allows the ring  210  to stretch over the disk  195  for installation and allows the seal ring  210  to compress or deform slightly in response to pressure forces and during assembly. 
         [0030]    With reference to  FIG. 5 , the seal ring  210  includes an inner space  230 , a first leg  235 , a second leg  240 , and an outer portion  245 . The inner space  230  is sized to receive a portion of the disk  195  without having to deform significantly. In preferred constructions, the inner space  230  defines a width that is about equal to the thickness of the disk  195 . In the illustrated construction, the inner space  230  is U-shaped and includes a semi-circular or curved bottom. However, other constructions may include flat bottoms or other shapes as desired. 
         [0031]    The first leg  235  and the second leg  240  extend from the outer portion  245  and cooperate to define the inner space  230 . Each of the first leg  235  and the second leg  240  includes a substantially planar inner surface  250  that defines one side of the inner space  230  and a frustoconical outer surface  255  or face that extends from the innermost diameter to the outer diameter. In the illustrated constructions, the frustoconical surfaces  255  taper from a first width to a second smaller width in a substantially uniform and consistent fashion. In other constructions, the taper or slope of the surface  255  may vary, there may be a planar portion, or the taper could be reversed as may be required for the particular application. 
         [0032]    When assembled onto the disk  195 , the planar inner surfaces  250  are parallel to and in contact with the top surface  200  and bottom surface  205  of the disk  195 . Because the seal ring  210  does not need to deform to receive the disk  195 , the inner surfaces  250  and the top surface  200  and the bottom surface  205  make very good contact along a significant portion of their length, thereby improving the seal therebetween. 
         [0033]    The outer surface  255  of the first leg  235  is in a facing relationship with and contacts the bottom surface  120  of the lid  95  and the outer surface  255  of the second leg  240  is in a facing relationship with and contacts the top surface  80  of the flange  70  during assembly. Because of the taper of the outer surfaces  255 , the first leg  235  and the second leg  240  contact first near the inner diameter. As the bolts  130  are tightened, the compressive force increases, thereby compressing and displacing the first leg  235  and the second leg  240 . As the first leg  235  and the second leg  240  displace, additional contact is made between the first leg  235  and the lid  95  and between the second leg  240  and the flange  70 . Thus, after assembly, the first leg  235  and the second leg  240  are most highly compressed near the inside diameter and are less compressed further toward the outside diameter. 
         [0034]    To assemble the separator  25 , the user places the seal ring  210  around the disk  195  of the separator element  140  and then positions the separator element  140  within the tank  60  with the second leg  240  of the seal ring  210  resting on the top surface  80  of the flange  70 . In constructions such as the one illustrated in  FIG. 7 , the user next positions the spacer or spacers  225  on the flange  70 . The lid  95  is then positioned above the flange  70  such that the bottom surface  120  of the lid  95  contacts the second leg  240  of the seal ring  210 . The bolts  130  are tightened to compress the seal ring  210  and provide a seal between the seal ring  210  and the lid  95 , the seal ring  210  and the top surface  200  of the disk  195 , the seal ring  210  and the bottom surface  205  of the disk  195 , and the seal ring  210  and the flange  70 . Thus, the use of the seal ring  210  provides four separate seals using only a single resilient seal ring  210 . 
         [0035]    Once assembled, the seal ring  210  electrically isolates the separator element  140  from the tank  60  and the lid  95 . With reference to  FIG. 8 , some constructions of the seal ring  210  include a tab portion  265  and a metallic grounding element  270  that passes through the tab portion  265 . The metallic grounding element  270  can include a staple that passes through the tab portion  265 . The metallic grounding element  270  contacts the disk  195  of the separator element  140  and also contacts the lid  95  to provide an electrical connection therebetween. The electrical connection assures that during operation, the separator element  140  is electrically grounded and no static charge can build up in the separator element  140 . Such a charge, if it were able to build-up could cause an undesirable spark. It should be noted, some constructions place the tab  265  band metallic grounding element  270  on the flange side of the separator element  140  such that the metallic grounding element  270  provides direct electrical contact between the tank  60  and the separator element  140 . The tank  60  and the lid  95  are electrically connected via the bolts. 
         [0036]    In operation, the prime mover  15  operates to rotate the screw elements  50  within the compressor housing. Rotation of the screw elements  50  draws in atmospheric air and compresses that air. A flow of oil is directed to the screw elements  50  to improve the seal between the elements  50 , to lubricate the screw elements  50 , and to remove heat produced during compression. The compressed air and oil forms an air-oil mixture that exits the compressor  20  via the compressor outlet  45  and flows to the separator inlet  85 . The air-oil mixture enters the separator  25  through an opening that is preferably off center, angled with respect to a radial line in the cylindrical tank  60 , and/or directed in a slight downward or upward angle. Using this arrangement produces a swirl of the inlet air-oil to establish a cyclonic flow. The cyclonic flow forces heavier particles, such as entrained oil, outward until the oil contacts the side surface of the tank  60  and separates from the air-oil mixture. Eventually, the air-oil mixture flows upward through the funnel member  90  and into the unfiltered portion  150  of the upper space  105 . The air-oil mixture then flows through the separator element  140  which operates to separate additional oil from the air-oil mixture. The air then exits the separator  25  via the outlet  55  which is in fluid communication with the filtered space  145 . In preferred constructions, the separator element  140  is arranged to separate enough oil from the air to deem the exiting air oil free (i.e., fewer than 10 parts per million by mass). 
         [0037]    The separated oil flows downward along the sides of the tank  60  to the bottom of the tank  60 . Additional separated oil drains from the separator element  140 , collects in the funnel  90  and eventually drains to the bottom of the tank  60  where it is removed and circulated back to the compressor  20 . In preferred constructions, the oil passes through an optional oil cooler  30  and a filter  35  before it is returned to the compressor  20 . Similarly, the now oil free air passes through a cooler  260 , a dryer, or other air treatment components before it is directed to a point of use. 
         [0038]    High pressure air from the filtered space  145  and the unfiltered space  150  abuts the first leg  235  and the second leg  240  respectively. The pressure applies a radial force to each of the legs  235 ,  240 , which operate to displace the legs  235 ,  240  radially outward. However, the pressure also displaces the legs  235 ,  240  in directions normal to the pressure force, thereby enhancing the contact pressure and seals produced by the seal ring  210 . 
         [0039]    Thus, the invention provides, among other things, a sealing system for a separator element  140  disposed in a tank  60 . Various features and advantages of the invention are set forth in the following claims.