An improved cryogenic vibratory mill apparatus, for receiving a liquid cooling fluid such as liquid nitrogen therein for cryogenic comminution of feed material supplied thereto, comprising:
- A. a housing means defining a grinding chamber means therein of generally cylindrical shape, said housing means defining a material inlet means in fluid flow communication with respect to said grinding chamber means to receive feed material passing therethrough for facilitating movement thereof into said grinding chamber means, said housing means further defining a material outlet means in fluid flow communication with respect to said grinding chamber means to receive material therefrom for exiting therefrom, said housing means further defining a cooling fluid inlet means in fluid flow communication with respect to said grinding chamber means, said cooling fluid inlet means for receiving liquid nitrogen for passing therethrough, said housing means further defining a cooling fluid outlet means in fluid flow communication with respect to said grinder chamber means and for allowing cooling fluid to exit therefrom;
- B. a cooling fluid distribution means for receiving liquid nitrogen passing through said cooling fluid inlet means for distribution thereof within said grinding chamber means;
- C. a plurality of nozzle means positioned within said cooling fluid distribution means to facilitate control of liquid nitrogen distributed therethrough;
- D. a plurality of longitudinal grinding rod members made of alloy steel and each defining a channel means extending longitudinally therethrough, said longitudinal grinding rod members further defining a channel inlet means and a channel outlet means in fluid flow communication with respect to said channel means to facilitate flow of fluid therethrough, said channel means also including a tapered channel section adjacent said channel inlet means to further facilitate movement of liquid nitrogen into said channel means, said channel inlet means being operatively positioned relative to said cooling fluid distribution means and in fluid flow communication therewith to receive liquid nitrogen therefrom for passing of the liquid nitrogen through said channel means and vaporizing thereof within said channel means and exiting of the cooling fluid therefrom through said channel outlet means to facilitate cooling along the length of said longitudinal grinding rod members, said fluid distribution means operative to dispense liquid nitrogen through said nozzle means into said channel inlet means such that at least sixty percent of the liquid nitrogen distributed therethrough passes through said channel means defined in said longitudinal grinding rod members to minimize flow of liquid nitrogen within said grinding chamber means in the area between said longitudinal grinding rod members;
- E. a vibrating means operatively attached with respect to said housing means for vibrating thereof and for urging movement of said longitudinal grinding rod members within said grinding chamber means to facilitate comminution of material positioned within said grinding chamber means, said vibrating means being operative to move said longitudinal grinding rod members through an arcuate cyclical orbit of approximately six to twelve millimeters in diameter extending perpendicularly to the axes thereof;
- F. a discharge plate means positioned within said housing means adjacent said grinding chamber means, said discharge plate means along with said housing means defining a discharge zone therewithin between said grinding chamber means and said material outlet means and between said grinding chamber means and said cooling fluid outlet means, said discharge plate means defining a discharge aperture means therein for allowing material to pass therethrough into said discharge zone and to said material outlet means and to allow cooling fluid to pass therethrough into said discharge zone and to said cooling fluid outlet means, said discharge aperture means defined in said discharge plate means being small enough to prevent movement of said longitudinal grinding rod members therethrough in order for containment thereof within said grinding chamber means;
- G. a material pre-cooling means for cooling of the feed material prior to passing through said material inlet means to further reduce the temperature within said grinding chamber means during comminution of material therein;
- H. an insulation means extending around said housing means to minimize thermal flow therethrough into said grinding chamber means;
- I. a cooling fluid outlet filter means extending across said cooling fluid outlet means to prevent movement of material outwardly therethrough, said cooling fluid outlet filter means comprising a filter cloth means;
- J. a feed plate means defining a feed aperture means therein, said feed plate means positioned within said housing means between said grinding chamber means and said cooling fluid inlet means to facilitate control of liquid nitrogen passing through said feed aperture means for guiding thereof toward said channel inlet means defined in said longitudinal grinding rod members positioned within said grinding chamber means to facilitate cooling thereof, said feed plate and said housing means together defining a fluid distribution chamber means between said cooling fluid inlet means and said feed plate means to accumulate a reservoir of liquid nitrogen for supplying thereof to said feed plate means for distribution thereof through said feed aperture means into said grinding chamber means, said feed plate means being positioned immediately adjacent said channel inlet means of said longitudinal grinding rod means to facilitate flow of liquid nitrogen therein and to minimize movement of material between said feed plate means and said longitudinal grinding rod members;
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- K. a pressurization means in fluid flow communication with said cooling fluid inlet means and said grinding chamber means to maintain the pressure within said grinding chamber greater than atmospheric pressure to further decrease the operating temperature therewithin.