PACKING ELEMENTS

Abstract: A packing element comprises an open-ended tubular member (1) having a row of perforations (3) adjacent each end of the member.

Description: Packing Elements This invention is concerned with improvements in and relating to packing elements for use in fluid-fluid contact apparatus. A wide variety of packing elements has been proposed for use in fluid-fluid contact apparatus. Examples of these include Raschig rings. Pall rings, Tellerette rings and Mini-rings. Such elements are used, for example, in apparatus such as distillation columns, reaction towers, gas scrubbing apparatus and the like. Many such elements take the form of or are based on a simple hollow tubular element which may be provided with inwardl directed ribs or tabs, apertures in the side walls, and/or flanges at their ends. It has now been found, in accordance with the present invention, that the overall e fectiveness of such ring-based elements may be improved by providing them with a row of relatively small perforations adjacent each end of the ring. Accordingly, the present invention provides a packing element comprising an open-ended tubular member having a row of perforations extending around the member adjacent each end of the member. As noted above, the perforations are relatively small and in this regard differ markedly from the apertures commonly found in packing rings. The perforations may be of any desired cross-section, polygonal or curvilinear, but are typically and conveniently circular in cross-section. The diameter of the perforations will, to some extent, depend upon the size of the element, larger elements having larger perforations and smaller elements having smaller perforations. Thus, for example, the dimensions of the perforations may be expressed as a percentage of the length of the tubular member; for example they may be from 1 to 5%, of the overall length of the tubular member. In absolute terms the perforations are suitably from 1 to 5 mm in diameter, preferably from 2 to 4 mm in diameter. The spacing between centres of the perforations in the rows will also depend upon the size of the packing element and thus may be expressed in terms of the diameters of the per orations, in which case the spacing is suitably from 2 to 5 diameters. The rows of perforations may be single rows or may comprise two or more rows, in which case perforations in 5 adjacent rows may be staggered. The end rows of perforations are suitably, in terms of perforation diameters are suitably from 1 to 5 diameters from the ends. The tubular member forming the body of the packing 0 element may be of any desired cross-section, polygonal or curvilinear, but is generally circular in cross-section, that is the tubular member takes the form of a hollow cyclinder. For convenience, in the following description reference will be made only to 5 such cylindrical tubular members. The ratio of the diameter of the tubular member to its height or length may be unity, as in the case of conventional raschig or Pall rings. However it is generally preferred that the ratio of diameter to height 0 be greater than unity, suitably at least from 1.5 :1 and preferably from 2:1 to 10:1, more preferably 2.5:1 to 5:1. I The tubular element is preferably provided with an outwardly directed flange at each end since this serves not only to strength the ring but to improve its effectiveness, particularly in combination with the rows 5 of perforations. Such flanges may extend generally normal to the surface of the tubular member or may be angled with respect to that plane so that the rim of the flange extends beyond the end of the tubular member both radially and longitudinally. 1° In order to inhibit possible nesting or interlocking of the elements, the tubular members are suitably provided with ribs or tabs extending inwardly from the walls of the member. Such ribs or tabs, which also serve to increase the available surface area of the 15 elements, may meet (and indeed may be joined) at or about the centre of the tubular member or may extend only part-way into the member. The walls of the tubular member may be provided with apertures in a conventional manner and located between 20 the rows of perforations. Such apertures will generally be of greater cross-sectional area than the perforations forming the rows and may. for example in the case of metal rings, be associated with inwardly directed tabs. The packing elements of the invention may be formed of any suitable material, commonly metal or plastics material. Suitable metals include mild steel, stainless steel and aluminium and its alloys. Suitable plastics materials include polypropylene and nylon. The packing elements of the invention may be employed in a wide variety of fluid-fluid contact apparatus, such as distillation or fractionation columns or gas scrubbing apparatus. The elements will, as is generally the practice, be supported upon liquid-pervious supports and may be stacked in an ordered array. However, the elements of the invention are particularly suitable for dumpiag into the apparatus and thus will generally be used in a so-called "dumped" array. In order that the invention may be well understood reference will be made to the accompanying drawings- in which: Figure 1 is a side view of a packing element in accordance with the invention; and Figure 2 is a plan view of the elements shown in Figure 1. δ As shown in the drawings a packing element in accordance with the invention comprises a tubular member 1 provided with flanges 2 at its ends and rows of perforation 3 adjacent each end. Tubular member 1 is further provided with apertures 4 from which spring inwardly directed tabs 5.

Claims: CLAIMS:- 1. A packing element comprising an open-ended tubular member (1) characterized in that the tubular has a row of perforations (3) extending around the member adjacent 5 each end of the member. 2. A packing element as claimed in claimed in claim 1 characterized in that the perforations have a diameter of from 1 to 5% of the overall length of the tubular member. 10 3. A packing element as claimed in claim 1 or claim 2 characterized in that the spacing between the centres of the perforations in a row is from 2 to 5 perforation diameters. 4. A packing element as claimed in any one of the 5 preceding claims characterized in that the tubular element has a ratio of diameter to height of at least 1.5:1. 5. A packing element as claimed in any one of the preceding claims characterized in that the tubular 0 member flanges (2) at each end. 6. A packing element as claimed in any one of the preceding claims characterized in that it has ribs or tabs (5) extending inwardly from the wall of the tubular member.

Inventors: MCKEOWN KEVIN JOSEPH, MCKEOWN, KEVIN, JOSEPH
Applicants: MASS TRANSFER LTD, MASS TRANSFER LIMITED
Application year: 1985
Main classification: B01D53
IPC codes: B01D53, B01J19