Abstract: A trapping plug with unique characteristics provides phase separators for cryogenic storage systems for space applications. The plug has a body of high-thermal conductivity metal such as OFHC copper and a multiplicity of holes of uniform, extremely small diameter and uniformly spaced extending through the body. The hole diameters and their uniformity in size and spacing enable precise design of an operating system using disclosed criteria. Hole diameters at the range of interest for systems for long-term storage of cryogenics such as liquid hydrogen, that is, 0.1 to 5.0 microns, may be provided in the plugs. Multiple plugs or clusters of plugs disposed in a plate may be used as required. A storage system making use of the trapping plugs also includes external vent lines and a flow regulator that controls flow of vapor through the vent lines.

Abstract: Perforated plates for use as filter media and devices for fluid injection and extrusion have a multiplicity of holes of a uniform size and a selected diameter as small as 0.5 micron. The plates are made by a "wire drawing" process wherein a sacrificial wire material in a plate metal can is repeatedly extruded and restacked, elongating the wire and reducing its diameter. Plates are then cut from the extruded composite, and the wire metal is removed by selective etching. By use of this process, perforated plates with several features unavailable previously are obtained. In particular, the plates have much smaller holes, higher porosity, and uniform size and shape, along with any desired thickness and a high length-to-diameter ratio. Such plates are ideally suited for use as a medium for various types of filters where removal of contaminants sized in the lower micron range is desired. Size and distribution of the holes in the plate are precisely controllable, enabling separations of materials of specific sizes.

Abstract: Perforated plates (10) having very small holes (14) with a uniform diameter throughout the plate thickness are prepared by a "wire drawing" process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er.sub.3 Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans (20) containing erbium and nickel metals in a stacked array (53) with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er.sub.3 Ni.

Abstract: Perforated plate heat exchangers and cryocoolers based on plates with extremely small, tubular holes are disclosed. The plates may have hole diameters down to the low micron size range and length-to-diameter ratios above unity and from 2 to 6 for typical applications. Such perforated plates function as tubes rather than screens and provide high efficiency, especially for compact cryocooler applications. The plates, which are made of a high thermal conductivity metal, and alternating spacers of low thermal conductivity material are disposed in an elongated stacked array of a large number of units such as 100. For use in a recuperative heat exchanger for a cryocooler employing the Linde-Hampson cycle, webs at the plate and spacer edges and a strip across the middle define two flow chambers, one for gas flow in each direction. One end of the array communicates with a high-pressure gas inlet for introducing gas in one chamber and a low-pressure gas outlet for removing gas from the other chamber.