Hydraulically dynamic mono-pig scraper

Abstract

The invention concerns a pig scraper for cleaning the inside wall of a coating agent conduit. The pig scraper includes a body insertable in the conduit and at least one sealing lip that seals against the inside wall of the conduit and extends parallel to a longitudinal axis of the body. A space is defined between the sealing lip and the body to form a pocket for enhancing the sealing of the sealing lip with respect to the conduit. The length of the sealing lip substantially prevents the lip from folding over on itself in response to a change in the direction of movement of the pig scraper in the conduit.

1 - 16 . (canceled)  
   
   
       17 . A pig scraper for cleaning an internal surface of a conduit conveying coating, comprising: 
 a body having a length and a longitudinal axis; and    at least one sealing lip extending and spaced from said body portion including an outer surface spaced from said internal surface of said conduit, an annular sealing edge projecting from said outer surface of said sealing lip generally triangular in cross-section adjacent to but spaced from a free end of said sealing lip including first and second faces extending at an acute angle to said internal surface of said conduit and an apex resiliently biased against said internal surface of said conduit.    
   
   
       18 . The pig scraper as defined in  claim 17 , wherein said first face of said sealing edge adjacent said free end of said sealing lip defines an angle relative to said internal surface of said conduit of between 25 and 60 degrees.  
   
   
       19 . The pig scraper as defined in  claim 18 , wherein said first face is generally planar and defines an angle of about 45 degrees to said internal surface of said conduit.  
   
   
       20 . The pig scraper as defined in  claim 17 , wherein said second face of said sealing edge spaced furthest from said free end of said sealing lip is defined at an angle relative to said internal surface of said conduit of between 10 and 60 degrees.  
   
   
       21 . The pig scraper as defined in  claim 20 , wherein said first face of said sealing edge defines an angle to said internal surface of said conduit of about 30 degrees.  
   
   
       22 . The pig scraper as defined in  claim 17 , wherein said body portion extends through said sealing lip having a flat end face.  
   
   
       23 . The pig scraper as defined in  claim 17 , wherein said body portion includes a cylindrical end portion having a diameter less than said sealing lip including a flat end face.  
   
   
       24 . The pig scraper as defined in  claim 17 , wherein said sealing lip has an axial length greater than 15% of an internal diameter of said internal surface of said conduit.  
   
   
       25 . A pig scraper for cleaning an internal surface of a conduit conveying a coating, comprising: 
 an integral body portion having a longitudinal axis, a length and opposed cylindrical end portions each having a flat end face; and    opposed resilient sealing lips integral with said body portion spaced from and surrounding one of said cylindrical end portions spaced from said flat end face each including an outer edge extending toward but spaced from said flat end face resiliently biased against said internal surface of said conduit.    
   
   
       26 . The pig scraper as defined in  claim 25 , wherein said outer surface of said resilient sealing lips each include an annular external edge projecting from an outer surface of said resilient sealing lips adjacent to but spaced from a free end of said sealing lips resiliently biased against said internal surface of said conduit.  
   
   
       27 . The pig scraper as defined in  claim 26 , wherein said annular edge is generally triangular in cross-section having first and second faces extending at an acute angle to said internal surface of said conduit and an apex resiliently biased against said internal surface of said conduit.  
   
   
       28 . The pig scraper as defined in  claim 27 , wherein said first and second faces of said annular edge are planar and said apex is a relatively sharp edge.  
   
   
       29 . The pig scraper as defined in  claim 25 , wherein said outer surface of said sealing lips are cylindrical and generally parallel to said internal surface of said conduit.