Abstract:
In, for example, a gas-liquid, liquid/liquid exchange column, perforated tray assemblies are provided comprising a plurality of adjacent tray sections with slots adjacent rounded leading edges of the sections, and catches extending along trailing edges which interlock in the slots of an adjacent section. This interlocking avoids the use of bolted joints which cause stagnant areas where sediment accumulation occurs, resulting in reduced gas-liquid and liquid/liquid contact, and the need for the tray sections to be frequently cleaned. Perforated domes may be provided on perforations to reduce stagnant areas.

Description:
[0001]     This is a continuation-in-part application of application Ser. No. 10/950,546, filed Sep. 28, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to an exchange column, perforated tray assembly.  
       BACKGROUND OF THE INVENTION  
       [0003]     Perforated tray assemblies are commonly used in exchange columns for effecting exchange between a descending liquid and an ascending gas or liquid in, for example, distillation, absorption or the like.  
         [0004]     In this specification “gas” includes vapor.  
         [0005]     Known perforated tray assemblies are composed of a number of adjacent sections which are bolted in position, and a problem that arises is that stagnant areas occur in the regions of the bolted joints causing sediment accumulation, thus reducing, for example, gas/liquid contact, and, depending on the particular use, can cause polymerization of components of the liquid which can accelerate even further sediment build-up. These problems can only be alleviated by increasing the column size, to increase the handling capacity, and frequent cleaning.  
         [0006]     There is a need for an exchange column, perforated tray assembly wherein no bolted joints are necessary for securing adjacent sections together and consequently stagnant areas adjacent the supports are significantly reduced, together with time needed to assemble and disassemble the tray sections, thereby increasing the handling capacity of the tray assembly and significantly reducing the time required, and intervals needed, to clean the tray assemblies.  
       SUMMARY OF THE INVENTION  
       [0007]     According to the present invention, there is provided an exchange column, perforated tray assembly comprising a plurality of tray sections, and connecting means for releasably connecting adjacent tray sections, the connecting means comprising, 
        a) a plurality of catch openings in one of those adjacent tray section, and     b) for each opening, a catch member attached to the other adjacent tray section, for releasably securing the tray sections by extending through that opening and contacting an underside of the said one tray section.        
 
         [0010]     The said one of the tray sections may have a rounded edge, the catch openings may extend downwardly in a marginal edge portion of the tray section adjacent the rounded edge, and the catch members have hump portions humping over the rounded edge, tongues which extend through the openings, and leading ends which latch the hump portions on the rounded edge by contacting the underside of the said one of those tray sections.  
         [0011]     The tray sections may be provided with catch openings along one side and catch members along an opposite side to the side containing the catch openings, so that tray sections are releasably secured together as strips.  
         [0012]     A central tray section may be provided with catch openings on all sides, and trays adjacent to the central tray section may be releasably secured thereto by catch members on these tray sections extending through the openings in the central tray section.  
         [0013]     Two central tray sections may be provided releasbly secured together by adjacent sides, and other sides of these tray sections may have catch openings for releasably securing other tray sections thereto by catch members attached to these other tray sections.  
         [0014]     The said one of those tray assemblies may have a rounded edge, and the catch openings may extend around a portion of the rounded edge.  
         [0015]     The catch openings may be upwardly extending slots, and the catch members may be tapered fins depending from the said other tray section and increasing in depth towards the end of, and extend beyond the underside of, the said other tray section, to contact the underside of the said one of the tray sections and be held thereagainst by resting in the slots.  
         [0016]     The portions of the fins which extend beyond the ends of the said other tray section may have rounded lower edges for easement into the slots.  
         [0017]     The said one of the tray sections may have a rounded edge adjacent the openings, and the edge of the said other tray that is adjacent the rounded edge may be shaped to rest thereagainst.  
         [0018]     At least perforations near the edges of the tray sections may form quincuncial patterns, with a central perforation thereof having an upper, annular seating therearound and providing a liquid path through that tray section, and a hollow, domed cap may be provided seated thereon, the domed cap having perforations.  
         [0019]     Perforations may be provided in the catch members to provide passage through the connecting means.  
         [0020]     For each tray section having catch openings, a stiffening plate may be provided depending from a portion of that tray section which is adjacent to the catch openings.  
         [0021]     The stiffening plates may have sloping, liquid collecting ends provided with drainage openings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     In the accompanying drawings which illustrate, by way of example, embodiments of the present invention,  
         [0023]      FIG. 1  is an angular view from above, of two adjacent sections of a perforated tray assembly of an exchange column,  
         [0024]      FIG. 2  is a similar view to  FIG. 1 , but viewing the adjacent sections closer to the horizontal,  
         [0025]      FIG. 3  is an enlarged, sectional scrap side view showing a catch member located in an opening in an adjacent tray,  
         [0026]      FIG. 4  is an enlarged, sectional scrap view of a perforation provided with a perforated, domed cap,  
         [0027]      FIG. 5  is a similar view to  FIG. 3  but of a different catch member,  
         [0028]      FIG. 6  is a similar view to  FIG. 3  but of a different catch member, and  
         [0029]      FIG. 7  to  9  are schematic plan views of different exchange column tray assemblies. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0030]     In  FIGS. 1 and 2  there is shown two tray sections, designated  1  and  2 , of a perforated tray assembly of an exchange column, and connecting means, generally designated  4  for releasably connecting these adjacent tray sections  1  and  2 .  
         [0031]     The connecting means  4  comprises, 
        a) a plurality of catch receiving openings, such as  6 , in the one of the adjacent tray sections designated  2 , and     b) for each opening, such as  6 , a catch member, such as  8 , attached to the other adjacent tray section designated  1 , for releasably securing these tray sections  1  and  2  by catching in the opening  6 .        
 
         [0034]     The catch openings extend downwardly in a marginal edge portion of the tray section  2 .  
         [0035]     As will be described later the tray sections  1  and  2  are intermediate of a perforated tray assembly and so, in this embodiment, are identical in that they are both provided with catch receiving openings  6  and catch members  8 .  
         [0036]     As is more clearly shown in  FIG. 3 , the tray sections  1  and  2 , have rounded edges  10 , and further comprise stiffening plates  14  adjacent the openings  6 . The catch members, such as  8 , comprise a hump portion  16  humping over the rounded edge  10 , a tongue  18  which extends through the openings  6 , and a leading end  20  which latches the hump portion on the rounded edge  10  by contacting the underside  22  of the tray section  2 .  
         [0037]     The stiffening plates  14  are provided with sloping, liquid collecting end portions  17  having drainage openings  19  ( FIGS. 1 and 2 ) for any liquid collecting on the stiffening plates  16 .  
         [0038]     Preferably, as shown in  FIGS. 1, 2  and  4  domed caps  22  with perforations  24  are provided in perforations, such as the perforation  26 , at least at positions where stagnant areas occur on the tray assembly, such as adjacent the column. The domed caps  22  may be provided centrally in quincuncial perforations patterns, and may have shoulders  28  for seating on a step  26  in the perforation  30 .  
         [0039]     In some embodiments, perforations  32  ( FIGS. 1 and 2 ) are provided in the rounded edges  10  and corresponding perforations  34  are provided in the catch members  8  for enhancing upward flow at these positions.  
         [0040]     The tray sections  1  and  2  are connected by tilting the tray section  1  to slide the catch members  8 , into the openings  6 , until the hump portions  16  rest on the rounded edge  10 , and then levelling the tray section  1  so that the leading ends  20  of the tongues  18  contact the underside  22  of the tray section  2 , and, latch the hump portions  16  on to rounded edge  10 .  
         [0041]     In  FIGS. 5 and 6 , similar parts to those shown in  FIG. 1  to  3  are designated by the same reference numerals, and the previous description is relied upon to describe them.  
         [0042]      FIG. 5  shows a sectional, scrap side view of a catch member  36  that enters, and rests in, an opening  38  in the rounded edge portion  10 . In this embodiment, the edge  40  of tray section  1 , that is next to the rounded edge  10  of the tray section  2  is shaped to rest on the rounded edge  10 .  
         [0043]      FIG. 6  shows a sectional, scrap side view of a catch member  42  which is a tapered fin, depending from tray section  1 , which increases in depth towards the end of, and extends beyond the underside of, the tray section  1  to contact the underside  22  of the tray section  2  and be held thereagainst by resting in a catch opening in the form of a downwardly extending slot  43  in the rounded edge portion  10 . Preferably the portion of the fin  42  which extends beyond the tray section  1  has a rounded lower edge for easement into the catch opening  43 .  
         [0044]     The embodiments shown in  FIGS. 5 and 6  latch the tray section  1  to the tray section  2  in a similar manner as that described with reference to  FIGS. 1 and 3 .  
         [0045]     FIGS.  7  to  9  are schematic plan views of exchange column tray assemblies incorporating tray sections of the type, or similar to, the tray sections designated  1  and  2  in  FIGS. 1, 2 ,  3 ,  5  and  6 .  
         [0046]     In  FIG. 7  shows a tray assembly in a liquid/liquid exchange column  44 , for receiving descending liquid from above, while ascending liquid through the tray assembly in contacted therewith.  
         [0047]     Perforated side tray sections  46  to  53  form part of the tray assembly and are provided so that the tray assembly conforms to the internal contour of the column  44 . The tray sections  46 ,  48  to  50  and  46 ,  51  to  53  are releasably secured together in this order in the same manner as the tray sections  1  and  2 . The perforated sheet  48  is then releasably secured to the tray section  1 ,  45  and  51  in the same manner as the tray sections  1  and  2 . The tray section  46 ,  48 - 49 - 50 ,  1 - 2 - 1 ,  1 - 2 - 1 , and  46 ,  51 - 52 - 53  are secured in the directions of the arrows, starting from the right hand side, and then the tray section  44  is added.  
         [0048]     In  FIGS. 8 and 9 , similar parts to those shown in  FIG. 7  are designated by the same reference numerals, and the previous description is relied upon to describe them.  
         [0049]     In  FIGS. 8 and 9 , an imperforate sheet  55  is provided to receive liquid from a downcomer, and a liquid drainage downcomer  45  is also provided.  
         [0050]     In  FIG. 8 , a central tray section  54  is provided with catch receiving openings on all sides, the tray section  56  and  58  have catch members on the sides adjacent to the tray section  54 , and catch receiving openings on all other sides. The tray section  60  and  62  have catch members on the sides adjacent to tray sections  56  and  58  respectively, and catch receiving openings on the other, opposing sides. The tray sections  64  to  68  have catch members on the sides adjacent to tray sections  60 ,  56 ,  54 ,  58  and  62  respectively. The tray section  54  is first placed in position, and then tray sections  54 - 56 - 60 , and  54 - 58 - 62  are connected in that order. The tray sections  48 - 1 - 1 - 51  are then connected to the tray sections  60 - 56 - 54 - 58 - 62  respectively and then sheet  55  is connected to tray sections  48 - 1 - 1 - 51 . The tray sections  64 - 65 - 66 - 67 - 68  are then connected to the tray sections  60 - 56 - 54 - 58 - 62  respectively. Thus tray sections  1 - 56 - 66 - 58  are releasably secured to the central tray section  54 .  
         [0051]     In this embodiment all of the tray sections are releasably secured together.  
         [0052]     In  FIG. 9 , similar parts to those shown in  FIG. 8  are designated by the same reference numerals, and the previous description is relied upon to describe them.  
         [0053]     In  FIG. 9 , the row of tray sections  1 - 58 - 67  of  FIG. 8  is omitted. In this embodiment, all of the tray sections are releasably secured together.  
         [0054]     The tray assemblies described with reference to  FIG. 1  to  9  may be used in, for example, liquid/liquid exchange columns and in liquid/gas exchange columns.  
         [0055]     In other embodiments of the present invention, the domed caps  22  may comprise upwardly deformed portions of the tray sections  1  and  2 .  
         [0056]     In yet other embodiments of the present invention, the domed caps are formed separately and welded over openings in the tray sections  1  and  2 .  
         [0057]     While the domed caps  22  are provided where stagnant areas occur on the tray sections  1  and  2 , as shown in  FIGS. 1 and 2 , the stepped perforations  26  may be provided in quincuncial patterns across the whole of the tray sections  1  and  2 , without the domed caps  22  on them. This arrangement is useful in exchange columns where descending, relatively denser liquid gravitates downwardly through the stepped perforations  26  while vapor ascends through tray perforations around the stepped perforations  26 . Also, perforations  26  allow for a uniform downward liquid distribution through tray sections  1  and  2 .