Flame holder system

{
  "publication_number": "US10072840B2",
  "country": "US",
  "kind": "B2",
  "title": "Flame holder system",
  "abstract": "A flame holder system includes a modified torch body and a ceramic flame holder. Catch pin(s) are coupled to and extend radially out from the torch body. The ceramic flame holder has groove(s) formed in its inner wall that correspond in number and positioning to the catch pin(s). Each groove starts at one end of the flame holder and is can be shaped to define at least two 90° elbows. Each groove is sized to receive one catch pin therein when the flame holder is fitted over the end of the torch body. The flame holder is then manipulated until the catch pin(s) butt up against the end of the groove(s).",
  "claims": [
    "1. A flame holder system, comprising: a plurality of catch pins adapted to be coupled to an outboard end of a torch body transporting combustible gases to the outboard end during a torch operation, each of said catch pins extending radially outward from the torch body; a flame holder having an outer wall and an interior cavity extending therethrough from an upstream first end to a downstream second end thereof to define an inner wall with said first end adapted to fit over the outboard end of the torch body, said flame holder having a plurality of grooves formed in said inner wall, each groove having a base wall spaced from said inner wall to define a depth, and side walls that are spaced apart to define a width, each of said grooves corresponding in depth and position to one of said catch pins, each of said grooves starting at said first end and shaped to define at least two turns, wherein each said groove is substantially U-shaped with a first segment having an open end and a final segment extending; shorter than the first segment, and the first and final segments being substantially parallel to a center line of said flame holder, each of said grooves sized to receive only a particular one of said catch pins therein when said flame holder is fitted over the outboard end of the torch body, said inner wall having a first portion adjacent said first end, a second portion adjacent said second end, and a third portion between the first and second portions, wherein the third portion includes a stepwise expansion in cross sectional area from the first portion, wherein the second portion has a divergent cross sectional area that increases from a location adjacent to the third portion to a location adjacent to the second end, wherein the second and third portions are configured to provide sudden expansion and recirculation of a fuel and air mixture to hold a flame immediately downstream of the third portion, and wherein the plurality of grooves are located in the first portion, further wherein the first, second and third portions define a single flow path; and a spring-loaded stop including a spring disposed between said spring-loaded stop and said catch pins and adapted to be coupled to the torch body for engaging said first end of said flame holder fitted over the outboard end of the torch body, and wherein the final segment of each of said grooves of said flame holder engages one of said catch pins when said spring applies a force axially to said flame holder to thereby retain said flame holder on the torch body.",
    "2. A flame holder system as in claim 1 wherein: said catch pins comprise two catch pins that are substantially diametrically opposed to one another on the torch body.",
    "3. A flame holder system as in claim 1 wherein: said flame holder comprises a one piece integral homogenous ceramic material.",
    "4. A flame holder system as in claim 1 wherein: an inner diameter of said flame holder varies between said first end and said second end.",
    "5. A flame holder system as in claim 3 wherein: said ceramic material comprises zirconium oxide.",
    "6. A flame holder system, comprising: a plurality of catch pins adapted to be coupled to an outboard end of a torch body transporting combustible gases to the outboard end during a torch operation, each of said catch pins extending radially outward from the torch body; a flame holder comprising a one piece integral homogeneous ceramic material, the flame holder having an interior cavity extending therethrough from an open first end to an open second end thereof to define an inner wall surface and an outer wall surface, with said first end adapted to fit over the outboard end of the torch body, said flame holder having a plurality of grooves formed in said inner wall, each groove having a base wall spaced from said inner wall to define a depth, and side walls that are spaced apart to define a width, wherein each said groove is substantially U-shaped with a first segment having an open end and a final segment extending shorter than the first segment, wherein the first and final segments are substantially parallel to a center line of said flame holder, each of said grooves sized to receive one of said catch pins therein when said flame holder is fitted over the outboard end of the torch body, said inner wall having a first portion adjacent said first end, a second portion adjacent said second end, and a third portion between the first and second portions, wherein the third portion includes a stepwise expansion in cross sectional area from the first portion, wherein the second portion has a divergent cross sectional area, and wherein the second and third portions are configured to provide sudden expansion and recirculation of a fuel and air mixture to hold a flame immediately downstream of the third portion, and wherein the plurality of grooves are located in the first portion, and further wherein the first, second and third portions define a single flow path; and a spring-loaded stop including a spring disposed between said spring-loaded stop and said catch pins are adapted to be coupled to the torch body for engaging said first end of said flame holder fitted over the outboard end of the torch body, and wherein the final segment of each of said grooves of said flame holder engages one of said catch pins when said spring applies a force axially to said flame holder to there by retain said flame holder on the torch body.",
    "7. A flame holder system as in. claim 6 wherein: the first and final segments are substantially parallel to a center line of said flame holder.",
    "8. A flame holder system as in claim 7, wherein: each of said grooves is sized to receive only a particular one of said catch pins therein when said flame holder is fitted over the outboard end of the torch body.",
    "9. A flame holder system as in claim 6 wherein: said catch pins comprise two catch pins that are substantially diametrically opposed to one another on the torch body.",
    "10. A flame holder system as in claim 6 wherein: said integral homogeneous ceramic material comprises zirconium oxide.",
    "11. A flame holder system as in claim 6 wherein: an inner diameter of the second portion increases from a location adjacent to the third portion to a location that faces said open second end."
  ],
  "description_excerpt": "The invention was made in part by employees of the United States Government and may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.\n\nField of the Invention.\n\nThis invention relates to high temperature torches. More specifically, the invention is a flame holder system for use with high temperature torches.\n\nDescription of the Related Art\n\nPropane torches, or burners, typically have a hollow torch body that is finished with a hollow nozzle or “flame holder” as it is known. Existing flame holders are generally made from stainless steel, cast iron or, in some cases, a ceramic material such as alumina oxide. Stainless steel flame holders are attached using set screws that pass radially through the flame holder to engage the outer wall of the torch body. Ceramic flame holders are bonded (e.g., using a ceramic adhesive) to the torch body.\n\nExisting flame holders present problems in applications requiring high temperature operation and/or extended operation times. Flame holders made from metal oxidize quickly on the outer walls thereof and subsequently experience spalling or flaking. If the operating temperatures are high enough, metallic flame holders will melt thereby requiring replacement of the flame holder, However, when the flame holder melts, it is difficult or impossible to disengage the set screws, in which case the whole torch is often discarded.",
  "cpc": [
    "F23D 14/58",
    "F16B 2200/71",
    "F23D 14/52",
    "Y10T 403/587"
  ],
  "ipc": [
    "F23D 14/46",
    "F23D 14/52",
    "F23D 14/58"
  ],
  "assignees": [
    "National Aeronautics and Space Administration NASA"
  ],
  "inventors": [
    "Henry H. Haskin",
    "Peter Vasquez"
  ],
  "filing_date": "2013-09-09",
  "publication_date": "2018-09-11",
  "grant_date": "2018-09-11",
  "priority_date": "2007-09-25",
  "application_number": "US-201314021325-A",
  "family_id": "40472031",
  "cited_by_count": 0,
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}