Metal working – Method of mechanical manufacture – Combined manufacture including applying or shaping of fluent...
Reexamination Certificate
1998-10-28
2001-08-21
Echols, P. W. (Department: 3726)
Metal working
Method of mechanical manufacture
Combined manufacture including applying or shaping of fluent...
C083S660000, C493S061000, C493S437000, C493S440000
Reexamination Certificate
active
06276045
ABSTRACT:
The present invention relates to apparatus and method for making filters or structured packing elements employed for fluid contacting systems, for example, such as for use with a distillate tower, mixers or catalytic distillation, and more particularly, for fabricating sheet material elements made of porous sintered metal fibers.
Of interest is commonly owned copending patent application Ser. No. 2539 entitled Structural Packing and Element Therefor filed Jan. 2, 1998 in the name of Bettina Paikert et al.
Sintered metal fiber sheets, for example, stainless steel fibers 8-25 &mgr;m (microns) in diameter, can be employed, for example, to make structured packing elements for distillate towers, fluid mixers or catalytic distillation. An example of such packing elements is disclosed in the aforementioned copending application. The material forming the elements has approximately 80-95% voids and may be more or less in certain implementations. The material, which can be, for example, initially formed in flat sheets, may have a thickness of about 50 &mgr;m to about 2 mm.
Examples of catalytic structures are disclosed in U.S. Pat. Nos. 4,731,229 to Sperandio, 5,523,062 to Hearn, 5,189,001 to Johnson, and 5,431,890 to Crossland et al. For example, the '229 patent discloses reactor packing elements comprising alternating fluted and unf luted parts with troughs that are inclined relative to the vertical. Apertures are provided in the sheet material to provide reagent communication flowing through the packing.
As a further example, a structured packing including vortex generators and fluid communication apertures is disclosed in the aforementioned copending application. As shown therein and in the patents mentioned above, structured packing is also provided with undulations, corrugations or pleats to enhance the fluid processing.
A highly porous sintered fibrous sheet material or any other easily compressible deformable material may have the stiffness of and an apparent consistency of conventional cardboard material although comprising metal fibers and is stronger than paper of cellulose fibers. Such material has a high surface to void volume.
The problem with such material is that it is not compressible without permanent deformation and is readily subject to permanent deformation similar to sheet paper board. Unlike cellulose fibrous paperboard material which is resilient when compressed, sintered metal fibrous material when compressed is permanently deformed. This substantially reduces its void volume and either destroys or negatively impacts on the material's function as a filter, a distillation tower and so on. This deleterious effect may be especially so where the fibers are coated with a catalyst for use. For example, in a catalytic distillation process.
Like paperboard, the metal fibrous material is easily deformed, creased and folded, which deformations, creases and folds form undesirable permanent defects in the sheet material. These properties of the material and its sensitivity to compressive pressures and deformation make it difficult to fabricate into complex shapes. For example, as noted above, distillation packing elements typically are formed with vortex generators and folds forming pleats or undulations. Such deformations are required to be introduced in the flat sheet material without compressive loads on the remainder of the sheet surface.
Prior art paper board processing machinery is not suitable for such metal fibrous material. Such machinery tends to process the sheet material with compressive loads, which for resilient paperboard, is not a problem. Such loads are not tolerated without permanent deformation, however, for the sintered metal fiber material. Such loads would permanently deform the fibrous metal material undesirably.
The present inventors recognize a need to provide a process and apparatus for producing a high void to surface area metal fibrous material with or without vortex generators and the like, folds and the like without undesirable permanent deformation of the material. Advantageously, the present inventors recognize such processed material may be employed as a structured packing material that may or may not be coated with a distillation catalyst for reaction processing of the fluids in a distillation tower.
A method according to the present invention for forming a compressible sheet material that permanently distorts in response to a compression load thereon comprises the step of forming a surface feature in the sheet material at a localized region with negligible compression load distortion of the material in the regions of the material adjacent to and externally of the region.
In one aspect, the step of forming comprises forming a foldline channel.
In a further aspect, a further step comprises piercing the material at a piercing site adjacent to the localized region.
In a further aspect, the step of forming includes forming a plurality of spaced foldline channels each at a localized region and then bending the material about each of the channels.
In a further aspect, the step of forming includes forming a plurality of channels in the material with each channel forming a different localized region.
In a still further aspect, the material has opposing broad surfaces, the method further including forming the channels linear and parallel to each other and in the opposing surfaces of the material.
The channels in the opposing surfaces may each lie in a plane normal to the material, the channels on the opposing surfaces lying in alternating planes.
In a further aspect, the step of bending the material about the channels bends the material with negligible compression distortion of the material externally the creases.
The bending in a further aspect includes bending the material in alternating opposite directions to form an undulating material.
In a still further aspect, the material lies in a plane, the method including piercing the material in a given shape and simultaneously bending the shaped pierced material to form tabs extending from the plane.
The material preferably comprises fibrous elements forming a porous member of a given volume.
The elements are preferably metal fibers and the material comprises voids of at least about 80% of the volume.
The step of forming may comprise compressively distorting the material at a distortion region.
An apparatus according to the present invention for forming a compressible material that permanently distorts in response to a compression load of a given magnitude comprises means for holding the material in a fixed position with negligible compression load distortion of the material; and means coupled to the means for holding for forming the held material with a surface feature at a localized region while providing negligible compression load distortion in regions of the material adjacent to and externally the formed region.
In one aspect, the means for forming comprises means for forming the material with a foldline channel.
In a further aspect, means are included for piercing the material at a piercing site adjacent to the localized region.
In a still further aspect, the means for forming includes means for forming a plurality of spaced foldline channels at a corresponding localized region and means for bending the material at each of the channels with negligible distortion of the material external the channels.
In a still further aspect, the means for forming the surface feature includes means for compressively distorting the material in the localized region.
Apparatus for non-compressively holding a sheet material of a given thickness value according to a further aspect of the present invention comprises a base; first and second overlying plates each with facing broad surfaces secured to the base in spaced relation for receiving the material therebetween; and means for relatively displacing the plates from a first position to a second position toward and spaced from each other a distance no less than the value so that the plates do not compress said received material.
REFERENCES:
patent: 23582
Büchi Franz
Dubach Peter
Griffin Timothy
Lloyd Jonathan
Paikert Bettina
ABB Lummus Global Inc.
Bain Carella Byrne
Echols P. W.
Olstein Elliot M.
Squire William
LandOfFree
Method and apparatus for making structured packing element does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for making structured packing element, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for making structured packing element will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2465956