Abstract: A chromatographic column is terminated with a fitting for connecting the column to an end flow tube. The fitting is provided with a column terminator element comprising a solid rim-like housing having a central aperture therein and a duplex porous disc positioned within the aperture and secured to the housing. The porous disc comprises a main body portion providing pores having a first relatively higher micron rating and a thin layer on one surface providing pores having a relatively lower micron rating and a higher pressure drop thereacross. The thin layer is adapted to face toward the chromatographic column and the main body portion has a coarse pimpled surface opposite the planar surface to facilitate lateral fluid flow relative to the main body portion.

Abstract: A porous sintered metal chromatographic column terminator element is disclosed comprising a relatively low density central disc portion, an integral relatively high density rim portion peripherally circumscribing the central portion and an interface zone that integrally joins the rim and central portions. The relatively flat faces of the rim and central portions are essentially coplanar but are separated and delineated by a channel at the surface of the interface zone intermediate said coplanar faces. The integral porous element exhibits a permeability ratio between the central disc portion and the rim portion of at least 3:1. Additionally, the central portion exhibits a density up to about 70 percent of the density of solid material of the same composition while the density of the rim portion is greater than that of the central portion and is up to about 95 percent of that of solid material of the same composition.

Abstract: A porous filter is formed of sintered metal particles and is characterized by having sintered metal particles of relatively large size throughout and a thin subsurface area adjacent the upstream surface containing sintered metal particles of relatively small size, thus providing a thin area of relatively small pore size adjacent the upstream surface while the remaining major portion of the filter has a relatively large pore size. The filter is particularly useful as an inertial filter and as a support for reverse osmosis membranes.

Abstract: A porous isopermeable tubular inertial filter with a large pore size has a slurry of fine particles flowed through it while an effluent is withdrawn through a jacket disposed about it until a thin inner layer of pores become clogged by the fine particles. The filter is then dried and the fine particles sintered in place to provide an inertial tubular filter with a upstream inner surface having a thin layer providing a high degree of filtration supported by the larger pore tubular filter.

Abstract: A gas transport system for powder has a delivery pipe having an end portion of porous material having a pore size smaller than the particles of the powder. The porous end portion is surrounded by a jacket in which a vacuum is drawn to draw off transport gas and reduce filter capacity which would otherwise be required to remove it. Pulses of pressure are periodically introduced into the jacket to clear particles from the inside of the porous end portion. The vacuum is drawn in the jacket through a vacuum line containing a constriction through which a nozzle discharges high pressure gas at intervals to provide the pulses of pressure in the jacket. This system is particularly effective when used in the production of uranium oxide.