Patent Publication Number: US-2016243479-A1

Title: High performance pre-cleaner and method

Description:
This application is being filed on 22 Oct. 2014, as a PCT International Patent application and claims priority to U.S. Provisional patent application Ser. No. 61/895,682, filed Oct. 25, 2014. 
    
    
     TECHNICAL FIELD 
     This disclosure is directed to pre-cleaner tube assemblies for use in inertial type pre-cleaners, and methods of use. 
     BACKGROUND 
     Pre-cleaners using vortex separators are known. Usually, these types of pre-cleaners are used upstream of a regular engine air cleaner, frequently in dusty or off-road environments. Improvements over prior art pre-cleaners are desired. The improvements include low cost, low restriction, high performance, and low risk of plugging. 
     SUMMARY 
     In one aspect, a pre-cleaner tube assembly is provided. The pre-cleaner tube assembly includes an inlet tube having an inlet tube wall surrounding an interior volume and first and second open, opposite ends. A vane arrangement is oriented within the inlet tube wall adjacent to the first open end. The inlet tube wall defines a slot adjacent to the second open end. An outlet tube has an outlet tube wall surrounding an interior volume, an open entrance end, and an opposite open exit end. The outlet tube wall has an exterior and an interior. The exterior of the outlet tube wall has a ramp extending upward as the ramp extends from a region adjacent to the entrance end toward a remaining portion of the outlet tube wall. The outlet tube is oriented in the inlet tube wall interior volume such that the entrance end and over 50% of a length of the outlet wall is within the inlet tube wall interior volume. 
     The exit end of the outlet tube can be exterior of the inlet tube wall. 
     The ramp can be on a radius of 1.5-3 mm. 
     The ramp can be on a radius of 2-2.5 mm. 
     The entrance end of the outlet tube can be circular with an internal radius and a central axis. A first distance is defined between the central axis and a radial outermost point of the ramp. A ratio of the first distance to the internal radius of the entrance end is between 1.5 and 1.3. 
     The ratio of the first distance to the internal radius of the entrance end is about 1.2. 
     At least 75% of a length of the outlet tube wall is within the inlet tube wall interior volume. 
     The second end of the inlet tube can be engaged against the exterior of the outlet tube wall and closer to the exit end of the outlet tube than the entrance end of the outlet tube. 
     The slot in the inlet tube wall can be an open slot extending from the second open end. 
     The slot in the inlet tube wall can extend a length of at least 50% of the length of the outlet tube. 
     The exit end of the outlet tube can have a diameter greater than a diameter of the entrance end of the outlet tube. 
     The inlet tube wall can have a constant outer diameter. 
     A pre-cleaner is provided having a housing with an air inlet, an opposite air outlet, a debris outlet, and an interior. A plurality of pre-cleaner tube assemblies as characterized above is operably oriented in the interior of the housing such that the first ends of the inlet tubes are at the air inlet of the housing; the exit ends of the outlet tube are at the air outlet of the housing; and of the slots are oriented toward the debris outlet. 
     The housing can include a cover that is a single molded piece as the inlet tubes. 
     The housing can include a housing body that is a single molded piece as the outlet tubes. 
     A method of using the pre-cleaner as characterized above can include directing air flow into the air inlet of the housing and into the first end of the inlet tubes; causing the air flowing into the first end of the inlet tubes to swirl with the vane arrangement; allowing centrifugal forces to direct at least some debris in a direction toward an inner surface of the inlet tube wall; allowing the air to flow through the outlet tube and out of the air outlet of the housing; and allowing at least some of the debris to exit the inlet tube through the slot and fall into the debris outlet of the housing. 
     A variety of examples of desirable product features or methods are set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing various aspects of the disclosure. The aspects of the disclosure may relate to individual features as well as combinations of features. It is to be understood that both the forgoing general description and the following detailed description are explanatory only, and are not restrictive of the claimed invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a pre-cleaner showing the air outlet and using pre-cleaner tube assemblies, constructed in accordance with principles of this disclosure; 
         FIG. 2  is a rear view of the pre-cleaner of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the pre-cleaner of  FIGS. 1 and 2 , the cross-section being taken along the line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of the pre-cleaner of  FIGS. 1-3 ; 
         FIG. 5  is a perspective view of one of the pre-cleaner tube assemblies used in the pre-cleaner of  FIGS. 1-4 , constructed in accordance with principles of this disclosure; 
         FIG. 6  is an end view of the pre-cleaner tube assembly of  FIG. 5 ; 
         FIG. 7  is a cross-sectional view of the pre-cleaner tube assembly of  FIGS. 5 and 6 , the cross-section being taken along the line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a perspective view of an outlet tube used in the pre-cleaner tube assembly of  FIGS. 5-7 ; 
         FIG. 9  is an end view of the outlet tube of  FIG. 8 ; 
         FIG. 10  is a side view of the outlet tube of  FIGS. 8 and 9 : 
         FIG. 11  is a cross-sectional view of the outlet tube of  FIGS. 8-10 , the cross-section being taken along the line  11 - 11  of  FIG. 9 ; 
         FIG. 12  is an enlarged cross-sectional view of a portion of the outlet tube of  FIG. 11 ; 
         FIG. 13  is a perspective view of the inlet tube used in the pre-cleaner tube assembly of  FIGS. 5-7 ; 
         FIG. 14  is a cross-sectional view of the inlet tube of  FIG. 13 ; 
         FIG. 15  is a perspective view of another embodiment of a portion of a pre-cleaner housing, the portion depicted being a cover holding a plurality of inlet tubes, constructed in accordance with principles of this disclosure; 
         FIG. 16  is a front view of the cover of  FIG. 15 ; 
         FIG. 17  is a cross-sectional view of the cover of  FIG. 16 , the cross-section being taken along the line  17 - 17  of  FIG. 16 ; 
         FIG. 18  is a perspective view of another portion of the pre-cleaner housing used with the cover of  FIGS. 15-17 , the portion depicted being a housing body having a plurality of outlet tubes, constructed in accordance with principles of this disclosure; 
         FIG. 19  is a front view of the housing body of  FIG. 18 ; 
         FIG. 20  is a cross-sectional view of the housing body of  FIGS. 18 and 19 , the cross-section being taken along the line  20 - 20  of  FIG. 19 ; and 
         FIG. 21  is an enlarged cross-sectional view of one of the outlet tubes depicted in  FIG. 20 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-4  show an embodiment of a pre-cleaner  10  constructed in accordance with principles of this disclosure. The pre-cleaner  10  includes a housing  12  having an air inlet  14  ( FIG. 2 ), and air outlet  16  ( FIG. 1 ) a debris outlet  18 , and an interior  20  ( FIGS. 3 and 4 ). The air inlet  14  and air outlet  16  are at opposite sides of the housing  12 . 
     In  FIG. 4 , in this embodiment, the housing  12  has a cover  22 , which generally defines the air outlet  16  of the housing  12 . The housing  12  also includes a housing body  24 . The cover  22  operably attaches and is securable to the housing body  24 . 
     The debris outlet  18  is illustrated as a tube  26  extending from the housing body  24 . The tube  26  of the debris outlet  18  is in open communication with the interior  20  of the housing  12 . In  FIGS. 1-3 , in preferred embodiments, the tube  26  of the debris outlet  18  is closed with an evacuation valve  28 , which will selectively open when there is sufficient debris collected in the tube  26  of the debris outlet  18 . 
     In the interior  20  of the housing  12 , the pre-cleaner  10  includes a plurality of pre-cleaner tube assemblies  30 . The pre-cleaner tube assemblies  30  are operably oriented in the interior  20  so that air flowing through the air inlet  14  of the housing  12  flows through the pre-cleaner tube assemblies  30 , and then the air exiting the housing  12  through the air outlet  16  will exit the pre-cleaner tube assemblies  30 . The pre-cleaner tube assemblies  30  remove at least some debris from the air and cause the debris to fall into the debris outlet  18 . More details on operation are described further below, after example pre-cleaner tube assemblies  30  are described. 
     Turning now to  FIGS. 5-7 , the pre-cleaner tube assembly  30  used in the pre-cleaner  10  is illustrated. The pre-cleaner tube assembly  30  includes an inlet tube  32 . The inlet tube  32  has an inlet tube wall  34  surrounding an interior volume  36 . The inlet tube  32  has first open end  38  and second open end  40  at opposite ends of the inlet tube  32 . 
     A vane arrangement  42  is oriented within the inlet tube wall  34  adjacent to the first open end  38 . The vane arrangement  42  includes a plurality of vanes  44 . The vanes  44  are constructed and arranged to induce swirling or a circular flow to air entering the inlet tube  32  through the first end  38 . When the air swirls around, centrifugal force causes debris in the swirling air to be directed toward and in some cases against an inner surface  46  of the inlet tube wall  34 . Some of that debris then exits the inlet tube  32  through a slot  48 . The slot  48  is defined by the inlet tube wall  34 , and it is adjacent to the second open end  40 . 
     In the examples shown in  FIGS. 5 and 13 , the slot  48  is an open slot extending from the second open end  40 . The slot  48  is further defined by being a circumferential cutout or circumferential void in the inlet tube wall  34 . The circumferential void extends across an arc of at least 30 degrees, in some cases at least 45 degrees, and in some cases at least 90 degrees. An axial length of the slot  48  measured as a percentage of an overall length of the inlet tube wall  34  between the first end  38  and second end  40  is at least 10%, no greater than 40%, and typically 15-25%. 
     In the example embodiment shown, the inlet tube wall  34  has a constant outer diameter, such that it forms a straight inlet tube  32 . 
     The pre-cleaner tube assembly  30  further includes an outlet tube  50 . The outlet tube  50  has an outlet tube wall  52  surrounding an interior volume  54 . The outlet tube wall  52  has opposite ends, one end being an open entrance end  56 , and the opposite being an open exit end  58 . 
     As can be seen in  FIG. 7 , the outlet tube  50  is at least partially oriented in the inlet tube interior volume  36 . In the example shown, the outlet tube  50  is oriented in the interior volume  36  of the inlet tube so that the entrance end  56  and over 50% of a length of the outlet tube wall  52  is within the inlet tube wall interior volume  36 . 
     Preferably, and as shown in  FIG. 7 , the exit end  58  of the outlet tube  50  is exterior of the inlet tube wall  34 . 
     In many preferred arrangements, at least 75% of a length of the outlet tube wall  52  is within the inlet tube wall interior volume  36 . 
     Still in reference to  FIG. 7 , the second end  40  of the inlet tube  32  is engaged against the exterior  60  of the outlet tube wall  52  at a location that is closer to the exit end  58  of the outlet tube  50  than the entrance end  56  of the outlet tube  50 . In the example shown, the second end  40  is within 20%, typically within 15%, of the exit end  58  as compared to the overall length of the outlet tube  50 . 
     When the outlet tube  50  is operably assembled within the interior volume  36  of the inlet tube  32 , the slot  48  in the inlet tube wall  34  extends the length that is at least 50% of the overall length (between entrance end  56  and exit end  58 ) of the outlet tube  58 . The slot  48  does not extend as far as the entrance end  56 . 
     Attention is directed to  FIGS. 8-12 , which illustrate various views of one example outlet tube  50 . The outlet tube wall  52  has exterior  60  and an opposite interior  62 . The exterior  60  of the outlet tube wall  52  includes a ramp  64  ( FIGS. 10-12 ). 
     The ramp  64  extends upward as the ramp  64  extends from a region adjacent the entrance end  56  toward a remaining portion of the outlet tube wall  52 . The ramp  64  helps to push large particles in a direction toward the inner surface  46  of the inlet tube  32 . When comparing pre-cleaner tube assemblies  30  that do not have a ramp  64  to pre-cleaner tube assemblies that do have a ramp  64 , it has been found that a greater percentage of water and particulate matter is removed from the air. 
     Many embodiments can be made. In this embodiment, the ramp  64  is on a radius of curvature at  66  ( FIG. 12 ) of between 1.5-3 mm. In many preferred systems, the ramp  64  is on a radius of 2-2.5 mm. 
     Still in reference to  FIG. 12 , the ramp  64  includes a radial outermost point  68 . This radial outermost point  68  is on radius of curvature, extending in an opposite curvature as radius  66 , of less than 1 mm, for example between 0.7 and 0.8 mm. 
     The entrance end  56  of the outlet tube  50  can be circular having an internal radius and a central longitudinal axis  70 . There is a first distance  72  in a radial direction between the outermost point  68  of the ramp  64  and the central axis  70 . A ratio of the first distance  72  to the internal radius of the entrance end  56  is between 1.1 and 1.3. In many preferred systems, the ratio of the first distance  72  to the internal radius of the entrance end is about 1.2. 
     As can be seen in  FIGS. 8-11 , in the example embodiment illustrated, the exit end  58  of the outlet tube  50  has a diameter that is greater than a diameter of the entrance end  56  of the outlet tube  50 . 
     In the example embodiment illustrated and in reference now to  FIG. 10 , the outlet tube  50  includes a ramp section  74 , on which the ramp  64  is located, which extends from the entrance end  56  to the point  68 . The ramp section  74  is less than 15% of the overall length of the outlet tube  50 . 
     Immediately adjacent to the ramp section  74  is a second section  76 . The second section  76  has a relatively straight outer wall  78 . The second section  76  has a length as an overall percentage of the overall length of the outlet tube  50  of between 20-35%. 
     Immediately adjacent the second section  76  and at an opposite end as the ramp section  74  is a diverging section  80 . The diverging section  80  diverges radially outwardly as its wall  82  extends from the second section  76  in a direction toward the exit end  58 . The length of the diverging section  80  as a percentage of the overall length of the outlet tube  80  can be between 40-60%. 
     Adjacent to the diverging section  80  and on an opposite side as the second section  76  is a third section  84 . The third section  84  is a relatively straight walled section with a length as a percentage of the overall length of less than 15%. The third section  84 , in the embodiment shown, defines the outermost outer diameter of the outlet tube  50 . 
     Immediately adjacent to the third section  84  is the exit end section  86 . It defines the exit end  58 . The exit end section  86  has a same internal diameter as the third section  84 , but as can be seen in  FIG. 10 , along the outer diameter, there is a radial inward step  88  between the third section  84  and the exit end section  86 . The length of the exit end section  86  is less than 15% of the overall length of the outlet tube  80 . 
     Turning again to the pre-cleaner  10  of  FIGS. 1-4 , it should now be appreciated how the pre-cleaner  10  operates. The pre-cleaner tube assemblies  30  are oriented in the interior  20  of the housing  12  such that each of the first ends  38  of the inlet tubes  32  are at the air inlet  14  of the housing. Each of the exit ends  58  of the outlet tubes  50  is at the air outlet  16  of the housing  12 . Each of the slots  48  is oriented toward the debris outlet  18 . 
     In some preferred embodiments, the housing cover  22  is molded as a single piece to include the outlet tubes  50 . This can be seen in  FIG. 4 . In the embodiment of  FIGS. 15-17 , to be described below, the housing cover  122  is molded as a single piece to include the inlet tubes  32 . 
     In some preferred embodiments, the housing body  24  is molded as a single molded piece as the inlet tubes  32 . In the embodiment of  FIGS. 18-21 , described below, the housing body  124  is molded as a single molded piece as the outlet tubes  50 . 
     In operation, air to be pre-cleaned is directed into the air inlet  14  of the housing  12  and into the first end  38  of the inlet tubes  32 . There is a step of causing the air flowing into the first end  38  of the inlet tubes  32  to swirl by use of the vane arrangement  42 . The swirling air then produces centrifugal forces, which will direct at least some debris in a direction toward the inner surface  46  of the inlet tube wall  34 . Air is then allowed to flow through the outlet tube  50  by entering through the entrance end  56 . The air in the outlet tube  50  then exits the outlet tube  50  through the exit end  58  and then out through the air outlet  16  of the housing  12 . At least some of the debris will not flow through the outlet tube  50 , but will fall by gravity through the slot  48  and then fall into the debris outlet  18  of the housing. 
     The pre-cleaner  10  using the pre-cleaner tube assemblies  30  was tested and compared to a standard pre-cleaner. The standard pre-cleaner did not have the ramp  64  on the outlet tube. Other differences included: the standard pre-cleaner had 39 tube assemblies, while the pre-cleaner  10  had 21; and the horizontal and vertical distance center-to-center of the standard was 39 mm and 39 mm, versus the pre-cleaner  10  was 70 mm and 65 mm. The flow through the both the standard pre-cleaner and the pre-cleaner  10  was 27.5 m 3 /min. The results were as follows: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Standard pre-cleaner 
                 Pre-cleaner 10 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Restriction (mbar) 
                 6 
                 4.3 
               
               
                   
                 Water separation (%) 
                 65.4 
                 85.7 
               
               
                   
                   
               
            
           
         
       
     
     Thus, from the above, it can be seen that the restriction through the pre-cleaner  10  drops by 28%, from 6 mbar to 4.3 mbar, while the percentage of water separation increases by 31%, from 65.4% to 85.7%, when compared to the standard pre-cleaner. 
       FIGS. 15-21  depict an alternate embodiment of a pre-cleaner  100  (part being shown in  FIG. 15  and part being shown in  FIG. 18 ) constructed in accordance with principles of this disclosure. The pre-cleaner  100  includes a housing having an air inlet  114  ( FIGS. 15-17 ), an air outlet  116  ( FIG. 20 ), a debris outlet  118  ( FIG. 20 ), and an interior  120  ( FIGS. 18 and 20 ). The air inlet  114  and air outlet  116  are at opposite sides of the housing. 
     The housing has a cover  122 . In this embodiment, as contrasted with the previous embodiment, the cover  122  defines the air inlet  114  of the housing. The housing also includes a housing body  124  ( FIGS. 18-20 ). The cover  122  operably attaches and is securable to the housing body  124 , in the same way as the previous embodiment shows the cover  22  secured to the body  24 . In this embodiment, the housing body  124  defines the air outlet  116 , in contrast to the embodiment of  FIGS. 1-14 . 
     The debris outlet  118  ( FIG. 21 ) is illustrated as a tube  126  extending from the housing body  124 . The tube  126  of the debris outlet  118  is in open communication with the interior  120  of the housing. The tube  126  may be closed with an evacuation valve, such as evacuation valve  28  shown in the embodiment of  FIGS. 1-14 . 
     In the interior  120  of the housing, the pre-cleaner  110  includes a plurality of pre-cleaner tube assemblies  30  as illustrated previously in  FIG. 7 . The pre-cleaner tube assemblies  30  are operably oriented in the interior  120  so that air flowing through the air inlet  114  of the housing flows through the pre-cleaner tube assemblies  30 , and then the air exiting the housing through the air outlet  116  will exit the pre-cleaner tube assemblies  30 . The pre-cleaner tube assemblies  30  remove at least some debris from the air and cause the debris to fall into the debris outlet  118 . Operation of the pre-cleaner tube assemblies  30  are the same as described above with respect to the embodiment of  FIGS. 1-14 . 
     In this embodiment, the inlet tubes  32  of the pre-cleaner tube assembly  30  have a central longitudinal axis  133  ( FIG. 17 ) which is angled at a non-zero and non-perpendicular angle relative a plane containing the air inlet  114 . In the previous embodiment, the inlet tube  32  had its central longitudinal axis as generally perpendicular to the plane containing the inlet  14 . The angle is shown at reference number  135 . Many different angles can be used. For example, the angle  135  can be greater than 45 degrees. The angle  135  can be less than 90 degrees. The angle  135  can be 60-80 degrees. In the embodiment show, the angle  135  is about 70 degrees. 
     The inlet tube  32  has the same structure as described above with respect to the embodiment of  FIGS. 5-7 . The description of the inlet tube  32  with respect to the previous embodiment is incorporated herein by reference. The same reference numerals are used for the same parts, and the same description applies. 
     The pre-cleaner tube assembly  30  includes outlet tube  50 , as previously described. In this embodiment, the outlet tube  50  is incorporated within the housing body  124 . In  FIG. 20 , each outlet tube  50  has a central longitudinal axis  151  which is at a non-zero and non-perpendicular angle relative to a plane containing the air outlet  116 . The angle is illustrated at reference numeral  153 . In general, the angle  153  will be the same as angle  135  to allow the outlet tubes  50  to be received within the inlet tubes  32 . The angle  153  can be greater than 45 degrees. The angle  153  can be less than 90 degrees. The angle  153  can be between 60-80 degrees. The angle  153  can be about 70 degrees. 
     The outlet tube  50  of the embodiment of  FIGS. 18-21  is the same as the outlet tube  50  of the previous embodiment, and the description of such is incorporated herein by reference. The same reference numerals are used for the same structure as described for the previous embodiment. 
     The operation of the pre-cleaner  110  is the same as the operation of the pre-cleaner  10  and as described above. 
     The above represents example principles of this disclosure. Many embodiments can be made.