Patent Application
20200197955
The present invention generally relates to compressors having a breather, and more particularly, but not exclusively, to centrifugal filtering of a mixed flow exiting a breather of a compressor.
Removing unwanted lubricant from a flow exiting a breather of a compressor remains an area of interest. Some existing systems have various shortcomings relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology.
One embodiment of the present invention is a unique centrifugal filter for a breather of a compressor. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for filtering flow of gas and lubricant from a breather of a lubricated compressor. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates.
With reference to
The compressor 50 includes a breather port 56 in fluid communication with a mechanical component working space of the compressor. Such mechanical component working space will be understood to include the space which houses the moving parts of the compressor 50 such as the rolling element bearings, gears, etc. The breather port 50 is useful to permit the ingress and egress of gases between ambient and the mechanical component working space as the compressor heats up, cools down, and is operated. In some instances gases may egress from the compressor 50 and entrain a flow of lubricant used for the moving parts. The lubricant that flows from the breather port 50 can take many different forms such as lubricant droplets. In one form the lubricant is an oil, but other types of lubricant are also contemplated.
The system in
Turning now to
The centrifugal filter 58 includes a stack 72 of filter discs capable of being spun at sufficient speed to aid in centrifugal removal of lubricant from the mixed flow 60. The stack 72 is mounted to a center support 74, both of which spin within a housing 76 of the centrifugal filter 58. A motor 78 is coupled with the center support 74 to provide the motive force necessary to spin the stack 72 at speed. The motor 78 can be any suitable device, including an electric motor. Furthermore, the motor 78 can, but need not, be enclosed by the housing 76. The motor can be supported by one or more bearings 80, while the support 74 to which the motor 78 is attached can also be supported by bearings 82. The bearings 80 and/or 82 can take any variety of forms, including but not limited to ball bearings (e.g. rolling element bearings supported by an inner race and an outer race).
During operation the motor 78 can spin the stack 72 at speed to aid in pulling in the mixed flow 60 which flows down the length of the support 74, through the interstitial space between adjacent discs (described further below), up an outer pathway between a radially outer portion of the stack 72 and the housing 76, and to be discharged via the outlets 70. Lubricant that is separated can be collected at the bottom of the space in which the stack 72 rotates before being discharged, such as through recycling action of the return line 64. In the illustrated embodiment the centrifugal filter 58 can include a lubricant collection chamber 84 which pools the lubricant for removal (e.g. via 64 and 66). Passages 86 can be provided to permit collection of separated lubricant in the lubricant collection chamber 84. It will be appreciated that the mixed flow 60 can enter the space between the center support 74 and the discs via the bearing 82, for example the space between rolling elements of the bearing. In other forms the mixed flow 60 can enter the space between the center support 74 and the discs via a central passage in the center support (see below regarding the central shaft 94) and then exit to the space between the center support 74 and the discs via openings formed in the center support (e.g. openings formed in the central shaft 94).
The motor 78 can be coupled to the center support 74 through a sliding fit 88 as depicted in
Turning now to
The arms 92 generally extend to an ending which engages the individual discs. The ending can take a variety of shapes, and in the illustrated embodiment the endings 98 take the form of protrusions 100. The protrusions 100 generally extend beyond the width of the arm 92. In the illustrated embodiment the protrusions take a circular shape, but other embodiments can include different forms on one or more of the arms 92. The circular shape of the illustrated embodiment is shown as having a diameter which extends beyond the thickness of the arm 92.
Further to the above, the arms 92 can extend away from the central shaft 90 any variety of distances. As will be appreciated in the depiction in
The arms 92, endings 98, and central shaft 94 can be individually produced and fastened together in some forms. Such fastening can take any variety of forms whether mechanical or chemical bonding, to set forth just a few non-limiting examples. In some forms two or more of the arms 92, endings 98, and central shaft 94 can be formed as a unitary whole.
The inner hub 106 forms a connection point with the arms 92, and in the illustrated embodiment the inner hub 106 is formed at an angle relative to a downward sloping working surface 108 of the discs 102a and 102b. The working surface 108 is generally conical shaped.
The discs used in the stack 72 can be identical in some embodiments, but in other embodiments the discs can be different. As shown in the illustrated embodiment of
The spacer 114 can be formed to ensure an offset between neighboring discs. The spacer 114 can take on a variety of forms, and in one embodiment is an extension of the fluid guide 112 into the hub 106. In other forms the spacer 114 can be offset from the flow guide 112. In some forms the spacer 114 can be absent from the disc if the flow guide 112 serves as a useful gap setter.
Either or both of the flow guide 112 and spacer 114 can be formed in any surface of the discs (102a and/or 102b). The illustrated embodiment depicts the guide 112 and spacer 114 as being formed in the outer surface of the conical shaped discs. In other embodiments, one or both of the flow guide 112 and spacer 114 can be formed on the inner side of the conical shaped discs.
In some forms disc 102a can have different flow features from disc 102b. For example, disc 102a may have the flow guide 112 formed on both inner and outer conical sides (with or without the spacers 114) while disc 102b is featureless. The same is true of disc 102b, it could include flow guides 112 on both inner and outer surfaces with the disc 102b being largely featureless.
Any of the center support 74 and discs can be made of plastic. Other material types are also contemplated herein. For example, in some embodiments the discs may be made out of a form of polyester resin used to make heat-resistant plastic films and sheets. One example of which is biaxially-oriented polyethylene terephthalate, a polyester film made from stretched polyethylene terephthalate. An example is a type of film dubbed “Mylar paper” available from DuPont.
The embodiments described herein are contemplated as being useful to remove lubricant particles as low as 0.15 micron, and in some embodiments as low as 0.1 microns.
The embodiments herein are also contemplated to have a construction which permits rotational rates of the disc stack 72 of 6,500-10,000 RPM.
One aspect of the present application includes an apparatus comprising: a centrifugal filter housing forming an open interior and having an inlet for receiving a flow of oil mist and air, a center support having an elongate main body structured to spin about an axis and disposed in the open interior of the centrifugal filter housing, the center support coupled with a plurality of arms each having a circumferential width and extending radially away from the main body, each of the plurality of arms having an end abutment surface, and a plurality of filter discs arranged sequentially along an axial length of the elongate main body, each of the plurality of filter discs having a plurality of recesses sized to receive the end abutment surface of each of the plurality of arms to form a complementary fit structured to encourage fixation of the plurality of the filter discs relative to the center support.
A feature of the present application includes wherein each of the plurality of arms coupled with a protrusion that extends circumferentially beyond the circumferential width of its respective arm of the plurality of arms.
Another feature of the present application includes wherein the protrusion is a cylindrical shape formed along the axial length of the at least one of the plurality of arms.
Still another feature of the present application includes wherein each arm includes an identical protrusion.
Yet another feature of the present application includes wherein the center support includes a cross sectional area having a width, wherein the at least one of the plurality of arms extends away from the center support a distance greater than the size of the width, and wherein a flow path is formed between the plurality of arms.
Still yet another feature of the present application includes wherein the center support is coupled to a motor on one end and a roller bearing element on the other, and wherein an inlet flow path formed to receive a mixed flow of oil and air is passed through interstitial spaces between the rolling elements of the roller bearing element.
Yet still another feature of the present application includes wherein the roller element bearing is a ball bearing.
A further feature of the present application includes wherein each filter disc of the plurality of filter discs includes a surface offset feature useful to abut and engage a neighboring disc to ensure a spacing interval between the adjacent discs.
A still further feature of the present application includes wherein the plurality of filter discs are arranged in an alternating arrangement with every other disc including an end flange.
A yet still further feature of the present application includes wherein the centrifugal filter housing includes have a threaded end adapted to fit a breather plug threaded connection of a compressor.
Another aspect of the present application includes an apparatus comprising: a centrifugal filter disc having an inner hub from which a conical filter element extends, the conical filter element having a flat pitch that follows a conical contour, the flat pitch interrupted by a plurality of flow guides that extend from a surface of the flat pitch, the inner hub oriented transverse to the flat pitch and having a plurality of gap setting features structured to abut a neighboring centrifugal filter disc to set a gap distance therebetween.
A feature of the present application includes wherein the inner hub of the centrifugal filter disc having an opening sized to receive a support structure, the opening having a rounded edge.
Another feature of the present application includes wherein the gap setting features are an extension of the plurality of flow guides.
Still another feature of the present application includes wherein the plurality of flow guides extend away from the flat pitch to aid in setting a gap distance with the neighboring centrifugal filter disc.
Yet another feature of the present application includes wherein the plurality of flow guides are formed as a spiral shape.
Still yet another feature of the present application includes wherein the flow guides are formed on an outer conical surface of the centrifugal filter disc.
Yet still another feature of the present application includes wherein the centrifugal filter disc includes a deflector flange formed in a radially outer end, the deflector flange turned to extend away from an inner conical surface of the centrifugal filter disc.
A further feature of the present application further includes a plurality of centrifugal filter discs to form a stack of centrifugal filter discs, the stack characterized by a disc configuration that alternates between a filter disc having the deflector and a filter disc without the deflector flange.
A still further feature of the present application includes wherein the plurality of flow guides extends from an outer conical side of the conical filter element.
A yet still further feature of the present application includes wherein the centrifugal filter disc is made of plastic.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
