Title of Invention	RANDOM DUMPED PACKING ELEMENT
Abstract	Tower packing elements in the fonn of arcuate body members with bridging loops can be made resistant to deformation by the provision of an embossment on the body member. It may also be further strengthened by providing a channel in the bridging loops. THIRTY RUPEES

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The present invention relates to certain kinds of tower packing elements such as are used in mass transfer and heat transfer applications in chemical processes. Such elements, which are often referred to as random dumped packings, are designed to give a large surface area for contact of gases with liquids while resulting in as low a gas phase pressure drop witliin the tower as possible. The elements are typically dumped into a vertical tower and piled to a considerable depth. There is therefore a tendency for the elements at the bottom to become deformed or flattened thus affording an increased resistance to flow through the tower and an undesirable pressure gradient within the tower. Tower packing elements are therefore designed to provide structures that resist detbrmation while still affording an open structure and a large surface area. Typical structures of the type referred to above are known as Pall rings and Raschig rings. As the names imply these are cylindrical in structure and are provided with various kinds of internal projections to increase the surface area. Such structures are resistant to crushing but do give rise to undesirable pressure drops in some applications. For such uses more open structures such as those described in USPP. 4,303,599; 4,333,892; and 4,576,763 are preferred. These are basically arcuate metal sheet structures with one or more strip elements cut from the metal of the arc and bowed inward within the arc so as to adopt a curvature opposite to that of tlie arc and fonn a bridge between the open ends of the arc. These bridging loops are primarily intended to define additional liquid passages and surfaces and to resist the tendency of the Elements to "nest" together. They provide little resistance to deformation on account of the relatively thin gauge of metal that is used to save weight. This concern to save weight is very important since the less the weight of an individual element, the smaller the accumulated force on elements at the base of a tower filled with such elements. Less force equals less tendency to deform and flatten. However thinner gauge metal makes the elements more easily deformed. There is therefore an inevitable compromise between the desire to make the elements lighter and yet have sufficient strength to support a load. A novel design has now been developed which greatly increases the resistance to deformation of arcuate random dumped packing elements. The design is adaptable to any of the presently existing dumped packings of the above type and will provide similar advantages in each. Incorporation of the design features of the invention can be accomplished with little extra expense using conventional manufacturing equipment. The design feature is particularly useful since it allows packings to be made more rigid while being lighter. Summary of the Invention The invention comprises a random dumped packing element having an arcuate body member and at least one bridging loop extending between the open ends of the arc of the body member said loop having a curvature opposite to that of the arc of the body member so as to enclose a space within the arcuate body and the bridging loop, said body member having an embossment extending essentially the length of the arc so as to provide a convex protrusion within the space bounded by the arcuate body member and the bridging loop. It is preferred that, to provide additional strength, the bridging loop is provided with a similar embossment extending essentially the length of the loop. Preferably the embossment forms a corresponding channel on the opposed surface of the loop. The embossment on the body member can be in the form of an added embossment deformed from the body member but more frequently it is in the form of a channel-shaped deformation running substantially the length of the convex surface of the body member, (and thus around the arc), so as to form a raised embossment on the opposed, (concave), surface of the arcuate body member. The channel may be deformed into the arc or alternatively out from the arc. The elements have the channel deformed into the arc, (such that the bead appears on the concave surface of the arcuate body member), so that liquid is not trapped in the bead. More than one such embossment can be formed if desired. The channel formed in the bridging loop may be formed in the convex surface or the concave and is generally quite shallow. The depth is generally less than 50% and more preferably less than 25% of the width of the loop such from about 10% to about 25% of such width. The function of the channel is to provide increased strength to the loop and excessive deformation of the metal strip forming the loop can be counter-productive in this respect, particularly when the gauge of the metal strip is thin. It is also possible to provide that the bridging loops have flanges in addition to the channels described above. It is also possible to add flanges to the body member to further strengthen it against deformation. Detailed Description of the Invention In addition to the features of the channels and embossments described above, the element may also comprise one or more pairs of projections extending into the space enclosed within the body member and the bridging loop(s), with one end of each of the pair of projections attached to the bridging loop in the vicinity of opposed ends thereof, the location and orientation of the projections being such that they project within the space enclosed by the body member and the bridging loop. The function of these projections is primarily to provide additional drip points in the element. In a preferred form of the invention the projections have the form of tabs formed from the material of the bridging loop by cutting and deforming the cut portions inwardly such that they approach but preferably do not contact one another. It is understood however that the tabs could be welded or otherwise affixed to the body member or a bridging loop. Cost generally makes this arrangement less attractive than stamping the structure from a single metal piece which is then formed appropriately to give the element its final shape. The tabs project toward one another such the angle at which they would meet is preferably less than 90°, such as about 60 to 75°. The projections can be formed from the material of the arcuate element itself by cutting the shape of the projection from a flat strip that is then bent to the desired configuration before, or simultaneously with, the forming of the projections by displacement of the cut material from the plane of the arcuate element. As will be appreciated, this is a highly advantageous approach to the manufacture of such elements since it can be perforiiied in a simple, mechanized, continuous sramping process. In addition to the projections described above, the arcuate elements of the invention can comprise any of the features that characterize the prior art arcuate packing elements. These include the use of a pair of bridging loops. The element can also have other tab projections that do not contact one another and merely function to define new contact surfaces and flow paths. In a particularly preferred embodiment of the invention the element, including the arcuate body member, the bridging loop or loops and the projections are formed from a single metal strip by cutting suitable lengthwise slits in the strip such that, when bent into an arcuate shape, bridging loops can be produced by forming at least one strip into the space enclosed by the arcuate body member and projections can be produced by forming strips that are now located in the bridging loop(s) into the space between the body member and the bridging loop(s). The embossment of the body member and the channels on the bridging loop(s) that characterize the present invention can be formed simultaneously or subsequently. Since the embossing of the bridging loop(s) may be done in the unformed piece, the embossments may run the full length of the piece. Thus, when forming the entire part, the embossment may extend from the ends of the body member on to the bridging loop(s) and back on to the opposite end of the body member in a continuous manner. The curvature of the arcuate element need not be uniform such that it has a cross-section perpendicular to the axis of tlie element that is an arc or a circle. In fact it is often desirable that this cross-section be parabolic in shape as in the case of the arcuate element described in USP 4,303,599. Accordingly the present invention provides a random dumped packing element having an arcuate body member and at least one bridging loop extending between the open ends of the arc of the body member, said loop having a curvature opposite to that of the arc so as to enclose a space bounded by the arcuate body and the bridging loop, wherein the body member has an embossment providing a convex protusion extending within and along essentially the length of the arc of the body and correspondingly a channel in the convex outward facing surface of the arcuate body member. With reference to the accompanying drawings, in which Figure 1 represents an end view of a first embodiment of an arcuate element according to the invention, the viewpoint being along the axis of the element. Figure 2 represents sheet of metal with cut lines marked therein which may be formed into the arcuate element illustrated in Figure 1. It does not however show the channels or embossment features which are imparted after the sheet has been slit as shown. Figure 3 is a side view of the element perpendicular to its axis. Figure 4 represents a sheet of metal with cut lines marked therein suitable for the production of an arcuate element having a particularly preferred configuration. Description of the Preferred Embodiments The invention is now described with reference to the urawmgs attached hereto which are understood to describe specific embodiments and are not to be taken as implying any necessary limitations on the essential scope of this invention. In Figure 1, an element, 1, comprises an arcuate body member, 2, with a longitudinally extending embossment, 6, and ends, 3. Two bridging loops, 4, having similar curvatures opposite to that of the body portion, are attached to the arcuate element adjacent the ends, 3, and span the gap between them. These loops are provided with channels, 7. Projections, 5, are formed from these bridging loops and project into the space between the body member and the bridging loops. Flanges, 8, are formed on the outer edges of the arcuate body member. Figure 2 shows a flat plate in which the cut lines have already been made to allow the plate to be bent and deformed into the arcuate element illustrated in Figure 1. Figure 3 illustrates the element of Figure 1 in side view to show more clearly the embossment and flange features of the invention. Figure 4 is similar to Figure 2 except for the formation in the piece of channels, 7, that, when the piece is formed into the packing element of the invention, will run from one end of the body member to the point at which the bridging loops join the arcuate body member, and then along the length of the bridging loops and thereafter to the opposed end of the arcuate body member. The Drawings illustrate an element with two bridging loops but it can readily be seen that a single bridging loop would also provide many of the advantages of the embodiment with the double bridging loops'that is illustrated. This too is within the scope of the invention as well as embodiments with even more bridging loops. As indicated above the arcuate elements of the invention can in addition have other features of the kind disclosed in the prior art without departing from the essential nature of this invention. WE CLAIM 1. A random dumped packing element having an arcuate body member and at least one bridging loop extending between the open ends of the arc of the body member said loop having a curvature opposite to that of the arc so as to enclose a space bounded by the arcuate body and the bridging loop, wherein the body member has an embossment providing a convex protusion extending within and along essentially the length of the arc of the body and correspondingly a channel in the convex outward facing surface of the arcuate body member. 2. An arcuate element according to Claim 1 in which the bridging loop has a channel extending essentially the full length of the loop, 3. An arcuate element according to Claim 2 in which the channel in the bridging loop extends beyond the loop and on to the ends of the arcuate body member. 4. An arcuate element according to Claim 2 in which the channel in the bridging loop is formed in the concave surface of the loop. 5. An arcuate element according to Claim 2 in which the channel in the bridging loop is formed in the convex surface of the loop. 6. An arcuate element according to Claim 1 which further comprises at least one pair of projections extending from the bridging loop adjacent the ends thereof and into the space between the body member and the bridging loop. 7. An arcuate element according to Claim 1 in which the body member is further provided with flanges along its edges. 8. An arcuate element according to claim 4 in which the embossment in the body member is formed by deforming the outer convex surface of the arcuate body member inwardly to form the channel in the convex outward facing surface of the arcuate body member. 9. An arcuate element according to claim 8 in which the channel in the bridging loop continues beyond the points at which the bridging loop joins the arcuate body member and continues to the ends thereof. 10. A random dumped packing element, substantially herein above described and illustrated with reference to the accompanying drawings.

Documents:

936-mas-1995 abstract.pdf

936-mas-1995 assignment.pdf

936-mas-1995 claims.pdf

936-mas-1995 correspondence-others.pdf

936-mas-1995 correspondence-po.pdf

936-mas-1995 description (complete).pdf

936-mas-1995 drawings.pdf

936-mas-1995 form-1.pdf

936-mas-1995 form-26.pdf

936-mas-1995 form-4.pdf

936-mas-1995 form-6.pdf

936-mas-1995 form-9.pdf

936-mas-1995 petition.pdf