Abstract:
A nozzle assembly for spraying a wash liquid towards a pulp mat, the assembly including an integral fastener-nozzle having a conduit for the wash liquid, an outlet to the conduit for discharging the wash liquid and an attachment to secure the fastener-nozzle to an aperture in a wash liquid pipe, and a wash liquid direction device extending outwardly from the pipe and adapted to direct the wash liquid from the outlet towards the pulp mat.

Description:
This application claims the benefit of and claims priority to Application Ser. No. 60/743,140 filed on Jan. 18, 2006 and is incorporated herein by reference. 

   BACKGROUND 
   The present invention relates to nozzles for a shower pipe to spray wash liquid onto a pulp mat. 
   Pulp is typically processed in mills by soaking or mixing wood pieces in tanks with chemicals that convert the wood pieces into pulp, and then bleaching pulp. The processing typically involves repeated stages of mixing the pulp with liquid and drawing the liquid out of the pulp by allowing the pulp to form mats on cylindrical vacuum drums. The pulp mats are washed by spraying wash liquid onto the mats. The wash liquid cleans chemicals out of the pulp mat. The wash liquid is sprayed from nozzles attached to liquid pipes spanning the width of the vacuum drums. There is a long felt need for liquid pipes and nozzle assemblies that uniformly spray wash liquid onto the mat and are inexpensive to manufacture and operate. 
   SUMMARY 
   A shower pipe and nozzle assembly for spraying a wash liquid on a pulp including: apertures in the pipe extending a length of the pipe spanning a width of the pulp mat, are laterally aligned along two or more rows such that adjacent apertures are in different rows, and the nozzle assembly includes a nozzle, a mounting block and a lip wherein the nozzle includes a hollow stem that attaches to the aperture and secures the nozzle assembly to the pipe, the block has a face that conforms to the pipe surface surrounding the aperture, an opposite face supporting the lip and an opening for the nozzle stem which is offset from a center of the block, and the lip includes a curved fan for turning wash liquid from the nozzle towards the pulp mat, a mounting surface abutting the opposite face of the block and a corner fitting over an edge of the block. The wash liquid flows through the pipe, the hollow stem of the nozzle and out of the nozzle as a stream that is generally tangential to the lip. The fan of the lip gradually turns the water towards the pulp mat and spreads the stream such that the water is sprayed uniformly on the mat. The multiple rows of apertures and nozzles project wash liquid towards the mat at different directions. 
   A nozzle assembly for spraying a wash liquid onto a pulp mat, the assembly comprising: a fastener-nozzle having an internal conduit for the wash liquid, an external fastener structure for attaching to an aperture in a wash liquid pipe and an outlet to the internal conduit for discharging the wash liquid, and a curved lip having a curved surface mounted to the pipe by the fastener-nozzle extending from the outlet to the internal conduct, the curved surface having an expanding width to convert a stream of wash liquid from the outlet to a sheet of wash liquid directed to the mat. A mounting block may be included in the assembly between the pipe and lip, wherein the block has an offset opening to receive the fastener-nozzle. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of a shower pipe and nozzle assembly, and a section of a pulp mat on a cylindrical dryer. 
       FIG. 2  is a cross-sectional view of the shower pipe and nozzle assembly, showing just one nozzle assembly. 
       FIG. 3  is a top view of the lip of the nozzle assembly. 
       FIG. 4  is an enlarged cross-sectional view of the nozzle assembly showing the hollow nozzle stem attached to an aperture in the pipe, a mounting block for the nozzle assembly, and a portion of the lip of the nozzle assembly. 
       FIG. 5  is a cross-sectional view of the shower pipe and nozzle assembly taken along line  5 - 5  in  FIG. 1  and showing a side view of a portion of the pulp mat and cylindrical dryer. 
       FIG. 6  is an exploded isometric view of the nozzle assembly and a portion of the pipe. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a shower pipe  10  that sprays a wash liquid  12  onto a pulp mat  14 . The mat (shown by dotted lines) forms on a rotating cylindrical vacuum drum  16 . The liquid wash is sprayed evenly and uniformly on the mat in one, two or more wash liquid sheets. The shower pipe  10  is positioned near the surface of the mat  14  and drum  16 . The shower pipe may be an extended cylinder spanning the width (W) of the vacuum drum. The pipe may be circular in cross-section, but may be rectangular, curvilinear or have some other cross-sectional shape. The pipe is preferably hollow and has an interior closed conduit  26  through which flows the wash liquid. A source  18  of liquid wash is connected to one or both ends of the pipe. 
   Wash liquid nozzle assemblies  20  are arranged along the length of the pipe  10 . The nozzle assemblies may be aligned in one, two or more rows extending laterally along the pipe. In the embodiment shown in  FIG. 1 , the nozzle assemblies are arranged along a first row  22  and a second row  24 . The rows may be angularly offset by an angle (A in  FIG. 5 ) that may be in a range of 3 degrees to 20 degrees. The nozzle assemblies  20  may be arranged to alternate between the rows along the length of the pipe. The nozzle assemblies may be equally spaced along the pipe and the spacing may be determined to provide a relatively uniform spray of wash liquid on the pulp mat  14 . The dotted lines in  FIG. 1  between the nozzle assemblies and the mat  14  indicate a uniform flow of two sheets of wash liquid being sprayed onto the mat. Preferably, the sprays from two adjacent nozzle assemblies on the same row (and separated by at least one other nozzle assembly on another row) do not overlap. 
     FIG. 2  is a cross-sectional view of the pipe  10  and a single nozzle assembly  20 . The interior surface of the pipe defines a wash liquid passage  26 . Along each row in the pipe are a series of equally spaced apertures  28  that receive a nozzle-fastener  30  of the nozzle assembly. The apertures  28  may be threaded to receive a threaded stem portion of the nozzle fastener. The apertures  28  may be tapered to ease insertion of the fastener. Wash liquid flows through a hollow passage  32  of the stem of the nozzle-fastener. This hollow passage has an inlet open to the liquid passage  26  and an outlet  34  for projecting wash liquid relatively tangentially to a lip  36  of the nozzle assembly. The nozzle-fastener also secures the nozzle assembly to the pipe, and extends through openings in the lip  36  and in the mounting block  46  ( FIG. 4 ). 
   As show in  FIG. 3 , the lip  36  may have a curved surface  38  that has a radially inward section (near the pipe) that is relatively tangent to the circumference of the pipe and perpendicular to the stream of wash liquid flowing from the nozzle. The lip includes a radially outward portion that both curves into the wash liquid stream and expands laterally. The lip may be a generally thin metal or plastic plate having a curved surface  38 , a mounting section  48  and a corner  50 . The mounting section  48  is a flat planar section that abuts an outside face  51  of the mounting block  46 . The corner  50  is a right angled lip that fits over an outside edge  52  of the mounting block. In top view ( FIG. 3 ), the curved surface of the lip is relatively narrow near the nozzle outlet  34  and expands into a fan-like shape. The curved surface  38  of the lip causes the water stream to spread out into a fan shaped liquid spray that flows to the pulp mat. 
     FIG. 4  is an enlarged view of a nozzle assembly  20  attached to the pipe  10 . The nozzle-fastener  30  includes a threaded stem  42  that screws into a threaded aperture  28  in the pipe. The head  44  of the nozzle-fastener may be a hexed bolt head. In one embodiment, the nozzle-fastener is a bolt having a hollow passage  32  that provides a wash fluid conduit from the liquid passage  26  in the pipe to the nozzle outlet  34 . The nozzle-fastener secures the nozzle assembly to the pipe. 
   The nozzle assembly may also include a mounting block  46  that is generally rectangular and has a first side that conforms to and abuts an outer surface of the pipe. The mounting block includes a second side, opposite to the first side, that is generally planar and provides a support surface for a planar mounting section  48  of the lip. An opening  54  through the mounting block receives the stem of the nozzle-fastener, but may not be threaded. The opening  54  in the block may be offset (see difference of lines D and C) from a center of the block. The offset allows the outlet  34  of the fastener-nozzle to be in close proximity to the radially inward portion of the curved surface  38  of the lip  36 . The second side of the mounting block abuts against the planar mounting section  48  of the lip  36 , when the nozzle-fastener secures the assembly  20  to the pipe. The corner  50  of the lip is a narrow strip that forms a 90-degree corner with respect to the mounting section  48  of the lip. When fitted to the mounting block, the corner  50  folds over an edge  52  of the mounting block and thereby assists preventing the lip from rotating about the mounting block and nozzle-fastener. 
     FIG. 5  shows wash liquid jetting from the outlet  34  of the passage  32  through the nozzle-fastener and flowing onto the curved surface  38  of the lip  36 . The lip spreads the water stream and turns the water stream towards a tangent of the pulp mat  14  and cylindrical drum  16 . Preferably, the spray of wash liquid from each row  22 ,  24  of nozzle assemblies is a generally uniform across the width of the mat. The angle (E, F) between the wash spray and mat depends on the row of the nozzle assembly and the amount of curvature in the lip. In the embodiment shown in  FIG. 5 , two sheets of wash liquid  55 ,  56  flow onto the pulp mat, where each sheet is from one of the two rows of nozzle assemblies. 
     FIG. 6  is an exploded view of the pipe  10  and a nozzle assembly  20 . A nozzle-fastener  30  is inserted through an opening in the mounting section  48  of the lip  36  and an opening  54  in the mounting block  46 . The stem  42  of the nozzle-fastener screws into a threaded aperture  28  of the pipe to secure the mounting block to the pipe and the lip to the mounting block. The corner  50  of the lip fits around an edge of the mounting block to prevent rotation of the lip. 
   While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.