Cleaning Systems and Methods for Rotary Screen Separators

Abstract

A cleaning system for a screen of a rotary screen separator for processing feed material comprising liquids and solids has a housing, an air source, and a conduit system. The housing defines at least one housing chamber, at least one inlet opening, and at least one outlet slot. The conduit system is operatively connected between the inlet opening of the housing and the air source. Air flows from the air source through conduit system, through the inlet opening, into the housing chamber, and out of the housing chamber through the at least one outlet slot in at least one air flow stream extending along a flow plane. The housing is arranged relative to the screen of the rotatory screen separator such that the air flow stream impinges on the screen to remove debris from the screen.

What is claimed is: 
     
         1 . A cleaning system for a screen of a rotary screen separator, the screen having a substantially cylindrical shape extending along a longitudinal axis for a screen length, the outer surface of the substantially cylindrical screen being perforated to admit a flow of liquid, the rotary screen separator for processing feed material comprising liquids and solids, the cleaning system comprising:
 a housing, extending substantially the screen length parallel to and offset from the longitudinal axis and situated outside of the outer surface of the screen defining at least one housing chamber, the housing chamber defining at least one inlet opening, and at least one outlet slot having an outlet slot axis extending parallel to the longitudinal axis and substantially the screen length, the outlet slot being in fluid communication with the housing chamber; and   an air source; and   a conduit system operatively connected between the inlet opening of the housing and the air source;   wherein, when activated, air flows from the air source through conduit system, through the inlet opening, into the housing chamber, and out of the housing chamber through the at least one outlet slot the air forms a laminar flow within a flow plane as the laminar flow impinges on the screen to remove debris from the screen.   
     
     
         2 . A cleaning system as recited in  claim 1 , in which the cleaning system comprises a plurality of housings each defining at least one housing chamber, at least one inlet opening, and at least one elongate outlet slot, where each elongate outlet slot is arranged to direct an air flow stream such that the air flow streams impinge on the screen to remove debris from the screen. 
     
     
         3 . A cleaning system as recited in  claim 1 , further comprising at least one water jet configured to spray water onto the screen of the rotary screen separator. 
     
     
         4 . The cleaning system as recited in  claim 1 , in which each of the at least one outlet slot defines a slot length dimension of 96-168″ and a slot gap dimension of 0.025-1.00″. 
     
     
         5 . The cleaning system of  claim 1 , wherein the housing defines a plurality of housing chambers longitudinally arranged within the housing and wherein the at least one outlet slot comprises a corresponding plurality of slots, each slot defined by its corresponding housing chamber and each slot axis being aligned to be colinear to each other and parallel to longitudinal axis such that the corresponding plurality of slots extend substantially the screen length. 
     
     
         6 . The cleaning system of  claim 1 , further comprising:
 a liquid outlet assembly comprising:
 at least one sprinkler situated outside of the screen and oriented parallel to each of the longitudinal axis and the outlet slot, the spray issuing from the at least one sprinkler to strike the outer surface to form a spray pattern whose major axis is parallel to a line where the flow plane intersects the outer surface of the screen nearest to the outlet slot. 
   
     
     
         7 . The cleaning system of  claim 6 , wherein the liquid outlet assembly additionally comprises:
 a liquid outlet housing in fluid communication with the at least one sprinkler, the liquid outlet housing being situated to extend substantially the screen length parallel to the longitudinal axis and residing outside of the outer surface of the rotary screen.   
     
     
         8 . The cleaning system of  claim 1 , further comprising:
 a debris sensor to:
 survey the outer surface of the screen; 
 to detect the presence of debris thereon; and 
 to generate DEBRIS signals indicative of debris when detected; 
 a controller to: 
 receive the DEBRIS signals the debris sensor generates; 
 to evaluate, at least, the DEBRIS signals the debris sensor generates; 
 selectively to activate the air supply source, in light of the received DEBRIS signals. 
   
     
     
         9 . A rotary screen separator for processing feed material comprising liquids and solids, the rotary screen separator comprising:
 a screen having a substantially cylindrical shape extending along a longitudinal axis for a screen length, the outer surface of the substantially cylindrical screen being perforated to admit a flow of liquid;   the rotary screen separator defining an input port and an output port and including:
 a drive system for rotating the screen; and 
 at least one vane structure; 
   a cleaning system comprising:
 a housing, the housing extending substantially the screen length parallel to and offset from the longitudinal axis and situated outside of the outer surface of the screen and defining:
 one housing chamber, at least one inlet opening, and 
 a plurality of outlet slots, each outlet slot having an outlet slot axis aligned to be collinear one with each other outlet slot axis, the plurality of outlet slots extending parallel to the longitudinal axis such that the plurality extends substantially the screen length, each of the plurality of outlet slots being in fluid communication with the housing chamber; 
 
 an air source for supplying air at the inlet opening to flow out of the plurality of outlets slot along a flow plane such that the air flow stream impinges on the screen to remove debris from the screen, and 
 a conduit system operatively connected between the inlet opening of the housing and the air source; 
   wherein operation of the drive system to rotate the separator causes the at least one vane structure to displace the feed material along the longitudinal axis;
 air flows from the air source through conduit system, through the inlet opening, into the housing chamber, and out of the housing chamber through the plurality of outlet slots in at least one laminar air flow stream extending along a flow plane; and 
 the housing is arranged relative to the screen of the screen separator such that the laminar air flow stream impinges on the screen to remove debris from the screen. 
   
     
     
         10 . A rotary screen separator as recited in  claim 9 , in which the flow plane extends substantially parallel to the longitudinal axis of the screen. 
     
     
         11 . A rotary screen separator as recited in  claim 9 , in which the flow plane substantially extends through an axis of the screen. 
     
     
         12 . A rotary screen separator as recited in  claim 9 , in which the cleaning system comprises a plurality of housings each defining at least one housing chamber, at least one inlet opening, and at least one elongate outlet slot, where each elongate outlet slot is arranged to direct an air flow stream such that the laminar air flow streams impinge on the screen to remove debris from the screen. 
     
     
         13 . A rotary screen cleaning system comprising:
 first and second housings each defining at least one housing chamber, at least one inlet opening, and at least one outlet slot having an outlet slot axis, the outlet slot axis of the at least one outlet slot of the first housing being collinear with the outlet slot axis of the at least one outlet slot of the second housing;   the at least one outlet slot of the first housing and the at least one outlet slot of the second housing being arranged so that air issuing from the at least one outlet slot of the first housing and the at least one outlet slot of the second housing forms a laminar air flow such that the laminar air flow stream impinges on the screen.   
     
     
         14 . A rotary screen separator as recited in  claim 13 , in which the cleaning system further comprises at least one water jet configured to spray water onto the screen of the rotary screen separator. 
     
     
         15 . The rotary screen separator as recited in  claim 13 , in which each outlet slot defines a slot length dimension of 96-168″ and a slot gap dimension of 0.025-1.00″. 
     
     
         16 . The rotary screen separator of  claim 13 , further comprising:
 a liquid outlet assembly comprising:
 at least one sprinkler situated outside of the rotary screen and oriented parallel to the longitudinal axis, the spray issuing from the at least one sprinkler to strike the outer surface to form a spray pattern whose major axis is parallel to a line where the flow plane intersects the outer surface of the screen in a line nearest to the outlet slot. 
   
     
     
         17 . The rotary screen separator of  claim 16 , wherein the liquid outlet assembly additionally comprises:
 a liquid outlet housing in fluid communication with the at least one sprinkler, the liquid outlet housing being situated to extend substantially the screen length parallel to the longitudinal axis and residing outside of the outer surface of the rotary screen.   
     
     
         18 . The rotary screen separator of  claim 13 , further comprising:
 a debris sensor to:
 survey the outer surface of the screen; 
 to detect the presence of debris thereon; and 
 to generate DEBRIS signals indicative of debris when detected; and 
   a controller to:
 receive the DEBRIS signals the debris sensor generates; 
 to evaluate, at least, the DEBRIS signals the debris sensor generates; 
 selectively to activate the air supply source, in light of the received DEBRIS signals.