Horizontal carbon dioxide snow horn with adjustment for desired snow

{
  "publication_number": "US6023941A",
  "country": "US",
  "kind": "A",
  "title": "Horizontal carbon dioxide snow horn with adjustment for desired snow",
  "abstract": "A method and apparatus is provided herein to produce solid CO 2 from liquid CO 2 wherein the solid CO 2 may be adjusted for level of agglomeration and can be continuously delivered through a snow horn in a horizontal or substantially horizontal orientation. The invention finds particular use in confined spaces such as between a freezer infeed conveyor and the freezer conveyor.",
  "claims": [
    "1. An apparatus for producing solid CO 2 from CO 2 in liquid form comprising: an inlet tube for receiving a flow of liquid CO 2; an outlet tube having a cross-section larger than said inlet tube for dispensing solid CO 2; and a porous member disposed within or at the discharge end of said inlet tube having a plurality of continuous, linked passages for the flow therethrough of liquid CO 2 and for the expansion of said liquid CO 2 to produce solid CO 2, wherein said inlet tube extends adjustably through said outlet tube at a first end of said outlet tube opposite from a second end of said outlet tube for discharge of solid CO 2, said inlet tube having a discharge end extending into said outlet Tube, and wherein the inlet tube discharge end is adjustable for length of extension into said outlet tube.",
    "2. An apparatus of claim 1 wherein said porous member is disposed adjacent to the inlet tube discharge end.",
    "3. An apparatus of claim 1 wherein said porous member is disposed between said inlet and said outlet tubes.",
    "4. An apparatus of claim 1 wherein said porous member comprises a material selected from the group consisting of porous metals, ceramics and plastics.",
    "5. An apparatus of claim 1 wherein said porous member comprises a disk having a plurality of passages of about 300μ in diameter.",
    "6. The apparatus of claim 1 wherein said porous member is disposed external to the outlet tube.",
    "7. The apparatus of claim 1 wherein the inner cross-section of the outlet tube increases from the first end toward the second end.",
    "8. The apparatus of claim 1 wherein said outlet tube comprises a snow horn.",
    "9. The apparatus of claim 1 wherein the outlet tube is disposed at a non-vertical angle, and wherein said apparatus is adapted to produce solid CO 2 when said outlet tube is at such angle.",
    "10. The apparatus of claim 9 wherein the outlet tube is disposed horizontally and wherein said apparatus is adapted to produce solid CO 2 when said outlet tube is horizontal.",
    "11. The apparatus of claim 9 wherein the outlet tube is disposed at a non-vertical angle, and wherein the inlet tube is in thermal contact along a portion of a length thereof with said outlet tube.",
    "12. The apparatus of claim 1 wherein said porous member comprises a disk having a plurality of passages having a diameter of about 200μ-300μ.",
    "13. The apparatus of claim 1 wherein said porous member comprises a disk having a plurality of passages having a diameter of less than about 200μ.",
    "14. A method for producing solid CO 2 from CO 2 in liquid form comprising the steps of: a) providing a snow horn disposed at a non-vertical angle, said snow horn having an inlet tube for receiving a flow of liquid CO, and an outlet tube having a cross-section larger than said inlet tube for dispensing solid CO 2 wherein said inlet tube extends adjustably through said outlet tube at one end of said outlet tube, said inlet rube having a discharge end extending into said outlet tube and wherein the inlet Tube discharge end is adjustable for length of extension into said outlet tube; b) passing liquid CO 2 through the snow horn inlet tube; and c) passing said liquid CO 2 through a plurality of fine, continuous, linked passages within or at the discharge end of said inlet tube to expand the liquid CO 2 and produce solid CO 2 in the snow horn outlet tube.",
    "15. The method of claim 14 wherein said plurality of fine, continuous, linked passages are within a porous member selected from the group consisting of porous metals, ceramics and plastics.",
    "16. The method of claim 14 wherein said snow horn outlet tube has an inner cross-section that increases from the first end toward the second end.",
    "17. The method of claim 14 further comprising means to maintain the temperature of the bottom of said outlet tube in the range at which CO 2 is a solid.",
    "18. The method of claim 17 wherein said means comprises placing said inlet tube in thermal contact along a portion of a bottom length of said outlet tube."
  ],
  "description_excerpt": "The present invention relates to CO 2 snow horns used in refrigeration systems and, in particular, to a method and apparatus for producing solid Co 2 snow from liquid CO 2.\n\nLiquid carbon dioxide exists at any temperature between the triple point temperature of -56.6° C. and the critical point temperature of 31° C. by compressing the carbon dioxide to the liquefaction pressure. At a temperature of from about 0° C. to 30° C., the liquefaction pressure is 505.4 psia (3.48 MPa) to 1045.8 psia (7.21 MPa). Liquid carbon dioxide used as a refrigerant, is generally maintained above the triple point pressure of 74.7 psia (0.52 MPa) and is subjected to a pressure drop to convert it to solid snow particles at a temperature of about 109° F. (42.8° C.). Presently available apparatus for creating liquid carbon dioxide snow generally utilizes an orifice for the snow producing pressure drop. A tube, usually having an expanding area, is used around the orifice to protect the snow from vaporization by warm air on its way to the use point. This tube is referred to as a \"snow horn\". Snow horns using present state-of-the-art orifice injection are positioned to discharge downwardly from a vertical orientation to freeze products, for example, between a freezer infeed conveyor and the freezer conveyor. They require considerable vertical distance such that excessive conveyor length is required to convey the infeed product back down to the freezer belt without product damage. When these horns are tilted to reduce the height requirement, they generally accumulate frost and often are not able to reliably discharge the created CO 2 snow.",
  "cpc": [
    "C01B 32/55",
    "C01B 32/50",
    "F25D 3/12",
    "Y10S 62/908"
  ],
  "ipc": [
    "B01J 19/00",
    "C01B 32/50",
    "C01B 32/55",
    "F25C 3/04",
    "F25J 1/00"
  ],
  "assignees": [
    "Praxair Technology Inc"
  ],
  "inventors": [
    "George D. Rhoades"
  ],
  "filing_date": "1998-07-22",
  "publication_date": "2000-02-15",
  "grant_date": "2000-02-15",
  "priority_date": "1998-07-22",
  "application_number": "US-12028098-A",
  "family_id": "22389310",
  "cited_by_count": 41,
  "citations": [
    "US2493759A",
    "US2791104A",
    "US3667242A",
    "US4015440A",
    "US4415346A",
    "US4375755A",
    "US4652287A",
    "US5749232A"
  ]
}