US3615251A - Oxygen-producing candle - Google Patents

Oxygen-producing candle Download PDF

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Publication number
US3615251A
US3615251A US884221A US3615251DA US3615251A US 3615251 A US3615251 A US 3615251A US 884221 A US884221 A US 884221A US 3615251D A US3615251D A US 3615251DA US 3615251 A US3615251 A US 3615251A
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Prior art keywords
oxygen
ignition
candle
screen
flash powder
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US884221A
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Frederick K Klenk
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MSA Safety Inc
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Mine Safety Appliances Co
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J7/00—Apparatus for generating gases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/02—Preparation of oxygen
    • C01B13/0203—Preparation of oxygen from inorganic compounds
    • C01B13/0218—Chlorate
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/02—Preparation of oxygen
    • C01B13/0296—Generators releasing in a self-sustaining way pure oxygen from a solid charge, without interaction of it with a fluid nor external heating, e.g. chlorate candles or canisters containing them

Definitions

  • the candles of this invention are suitable for use in oxygenproducing apparatus such as is shown in Bovard and Hamilton, U.S. Pat. No. 2,758,015.
  • oxygen producing apparatus such as is shown in Bovard and Hamilton, U.S. Pat. No. 2,758,015.
  • an oxygen candle burns in such apparatus, it must produce oxygen in a volume great enough to sustain life before the chemical in the apparatus, that reacts with exhaled breath to remove carbon dioxide and produce oxygen, is functioning well enough to do it alone.
  • This chemical reaction is retarded at low temperatures, as in the Artic and at high altitudes, so it is necessary that the oxygen candle perform reliably at low temperatures.
  • Government procurement regulations require testing of the apparatus at 30 C. as a satisfactory measure of low-temperature performance.
  • a powder primer is fired to ignite a flash powder; the flash powder ignites in turn an ignition core material that burns rapidly, and in turn ignites the main candle body to produce oxygen.
  • the manufacture of such candles even with the exercise of tight specifications and strict quality control practices, lots are frequently rejected because of total or partial ignition failure particularly at low temperatures.
  • This invention is based on my discovery that such ignition failures result from a failure of the flash powder to properly ignite the ignition core of the oxygen candle and that such failures can be substantially eliminated by disposing a metal screen between the flash powder and ignition core.
  • FIG. 1 is a plan view of the candle partly broken away to show the screen and oxygen producing material
  • FIG. 2 is a vertical section taken on line 11-11 of FIG. 1.
  • a cup 1 which is preferably cylindrical, is seated in the base 2 of a canister such as shown in U. S. Pat. No. 2,758,015.
  • the bottom of the cup is provided in its center with an opening registering with a similar opening in the base of the canister.
  • a flanged sleeve 3 extends up through these openings and has a threaded upper end on which a nut 4 is screwed to clamp the cup and canister base tightly together.
  • a primer 6 is mounted in the lower end of the sleeve, while a charge 7 of flash powder is pressed into the upper end of the sleeve.
  • a body 8 of oxygen-producing material of well-known composition that gives off oxygen while it is burning, has a recess 9 in its bottom so it can fit over nut 4, and a central cavity opening into the recess 9 leaving a peripheral shoulder 10.
  • the cavity is filled with an ignition core 11.
  • a metal screen 12 is situated in the recess between the ignition core and preferably abutting the nut 4 and the annular shoulder 10 formed by the end wall of the recess as well as the ignition core.
  • the flash powder does not extend to the end of nut 4 so that, in the preferred embodiment, the flash powder is spaced from the screen.
  • the screen may be made of any metal or alloy that will withstand the heat generated by the flash powder, suitably metals or alloys resistant to oxidation such as brass or stainless steel. Standard 10 to 50 mesh screens are suitable although larger or smaller mesh screens may be used if desired.
  • a means for filtering out smoke that may be produced by the burning candle.
  • This may consist of a dimpled metal plate supported on top of the candle body, a screen 13 on top of the plate, a layer or two of filtering material 14, another screen 15, and a ring 16 pressed down onto the latter by indentations 17 in the top of the cup around it.
  • the chlorate candle 8 may be a cast body or a compact of powdered or granular materials according to conventional practice.
  • Chlorate candles contain predominantly an alkali metal chlorate or perchlorate, usually sodium chlorate; a metal, usually iron, although other reactive metals may be used; and generally minor amounts of a binder such as fiberglas and other ingredients such as barium peroxide.
  • alkali metal chlorate or perchlorate usually sodium chlorate
  • a metal usually iron, although other reactive metals may be used
  • a binder such as fiberglas and other ingredients such as barium peroxide.
  • Representative suitable chlorate candle compositions are disclosed in U.S. Pat. Nos. 2,469,414, 3,089,855, 3,l74,936, 3,207,695 and 3,293,187.
  • the ignition core 11 is a conventional, easily ignited pyrotechnic that burns rapidly without flashing, suitably a compacted mixture of metal powder and an inorganic oxidizer with or without diluents, binders or other minor components.
  • the ignition core may contain the same material as the candle body, but with a higher amount of metal to give a faster burning rate.
  • Ignition cores may be staged, that is, having portions of different compositions having different burning characteristics.
  • suitable ignition cores may be a compact of from about 20 to 40 percent iron powder, from about 15 to 40 percent sodium chlorate, from about 10 to 20 percent barium peroxide, and from about 5 to 20 percent fiberglas.
  • a variety of ignition core materials are well known and have been used for reliably igniting chlorate candles.
  • the ignition core is ignited by flash powder 7, that may be any of the well known easily ignitable first-fire pyrotechnic mixtures that, when ignited, burn rapidly to produce a sudden temporary luminous flame. It is preferred to use a mixture of a finely divided metal, such as aluminum, magnesium, titanium, iron or nickel and an inorganic oxidizing agent, for example, alkali metal or alkaline earth metal nitrates, chlorates and perchlorates.
  • a finely divided metal such as aluminum, magnesium, titanium, iron or nickel
  • an inorganic oxidizing agent for example, alkali metal or alkaline earth metal nitrates, chlorates and perchlorates.
  • Flash powder 7 was from a single lot of a mixture of 30 percent nickel, 20 percent titanium, 45 percent potassium perchlorate and 5 percent infusioral earth.
  • the ignition core composition was 30 percent iron, 30 percent sodium chlorate, 25 percent fiberglas and 15 percent barium peroxide.
  • four candles failed completely to ignite and I4 candles generated less than one-half liter of oxygen in the first 15 seconds after ignition, a substandard amount.
  • the amount of oxygen generated in the first l5 seconds after firing ranged from 0 to 1.1 liters with an average of 0.67 liters.
  • this invention provides improved ignition is not known, it is believed the screen serves to disperse the effective area of the flame from the flash powder, prevents ignition core material from disengaging from the candle body, the core may shrink or become partially molten, and acts as a heat sink. It will be recognized that this invention will be advantageous in any oxygen candle ignition train in which an ignition core is ignited by a flash powder.
  • An oxygen candle comprising a body of material that produces oxygen on burning and a core of ignition material having an ignitable face, a recess in said candle having an end wall comprising said ignitable face, a metal screen covering and abutting said end wall, cover means closing said recess to form a chamber and supporting a body of flash powder within the chamber spaced from said screen, and means to ignite the flash powder from outside said chamber.

Abstract

In an oxygen-producing candle having an ignition core that is ignited by flash powder, improved ignition is obtained by disposing a metal screen between the ignition core and the flash powder.

Description

United States Patent 1111 3,615,251
[72] Inventor Frederick K. Klenk [56] References Cited Forward Township, Butler County, Pa. UNITED STATES PATENTS 1 PP 384,221 2,764,475 9/1956 Bovard et al 23/281 1 Flled 11, 1969 3 377 956 4/1968 Van Deene Emerson 102/102 [45] Patented Oct. 26, 1971 [73] Assignee Mine Safety Appliances Company Examiner-James y n,
Pittsbur h, Pa, At10rneyRonald H. Shakely [54] OXYGEN-PRODUCING CANDLE 4 Claims, 2 Drawing Figs.
52 U.S. Cl 23/281, 23/221,165/185,102/102,102/70 [51] Int. Cl BOlj 7/00 ABSTRACT: In an oxygen-producing candle having an igni- [50] Field of Search 23/281 tion core that is ignited by flash powder, improved ignition is 221; 165/185; 102/102, 103,70,37.8;252/186: obtained by disposing a metal screen between the ignition 187 core and the flash powder.
PATENTED 0m 2 6 I97! INVENTOR: H'ederick K. K lenk OXYGEN-PRODUCING CANDLE This invention relates to candles that generate oxygen as they are burned, and more particularly to such candles having improved ignition characteristics.
The candles of this invention are suitable for use in oxygenproducing apparatus such as is shown in Bovard and Hamilton, U.S. Pat. No. 2,758,015. When an oxygen candle burns in such apparatus, it must produce oxygen in a volume great enough to sustain life before the chemical in the apparatus, that reacts with exhaled breath to remove carbon dioxide and produce oxygen, is functioning well enough to do it alone. This chemical reaction is retarded at low temperatures, as in the Artic and at high altitudes, so it is necessary that the oxygen candle perform reliably at low temperatures. Government procurement regulations require testing of the apparatus at 30 C. as a satisfactory measure of low-temperature performance.
In the ignition train to ignite the candle, a powder primer is fired to ignite a flash powder; the flash powder ignites in turn an ignition core material that burns rapidly, and in turn ignites the main candle body to produce oxygen. In the manufacture of such candles, even with the exercise of tight specifications and strict quality control practices, lots are frequently rejected because of total or partial ignition failure particularly at low temperatures.
This invention is based on my discovery that such ignition failures result from a failure of the flash powder to properly ignite the ignition core of the oxygen candle and that such failures can be substantially eliminated by disposing a metal screen between the flash powder and ignition core.
The invention is illustrated in the accompanying drawings in which FIG. 1 is a plan view of the candle partly broken away to show the screen and oxygen producing material, and
FIG. 2 is a vertical section taken on line 11-11 of FIG. 1.
Referring to FIGS. 1 and 2, a cup 1, which is preferably cylindrical, is seated in the base 2 of a canister such as shown in U. S. Pat. No. 2,758,015. The bottom of the cup is provided in its center with an opening registering with a similar opening in the base of the canister. A flanged sleeve 3 extends up through these openings and has a threaded upper end on which a nut 4 is screwed to clamp the cup and canister base tightly together. A primer 6 is mounted in the lower end of the sleeve, while a charge 7 of flash powder is pressed into the upper end of the sleeve. A body 8 of oxygen-producing material, of well-known composition that gives off oxygen while it is burning, has a recess 9 in its bottom so it can fit over nut 4, and a central cavity opening into the recess 9 leaving a peripheral shoulder 10. The cavity is filled with an ignition core 11. A metal screen 12 is situated in the recess between the ignition core and preferably abutting the nut 4 and the annular shoulder 10 formed by the end wall of the recess as well as the ignition core. The flash powder does not extend to the end of nut 4 so that, in the preferred embodiment, the flash powder is spaced from the screen. The screen may be made of any metal or alloy that will withstand the heat generated by the flash powder, suitably metals or alloys resistant to oxidation such as brass or stainless steel. Standard 10 to 50 mesh screens are suitable although larger or smaller mesh screens may be used if desired.
Inside the upper part of the cup there are means for filtering out smoke that may be produced by the burning candle. This may consist of a dimpled metal plate supported on top of the candle body, a screen 13 on top of the plate, a layer or two of filtering material 14, another screen 15, and a ring 16 pressed down onto the latter by indentations 17 in the top of the cup around it.
The chlorate candle 8 may be a cast body or a compact of powdered or granular materials according to conventional practice. Chlorate candles contain predominantly an alkali metal chlorate or perchlorate, usually sodium chlorate; a metal, usually iron, although other reactive metals may be used; and generally minor amounts of a binder such as fiberglas and other ingredients such as barium peroxide. Representative suitable chlorate candle compositions are disclosed in U.S. Pat. Nos. 2,469,414, 3,089,855, 3,l74,936, 3,207,695 and 3,293,187.
The ignition core 11 is a conventional, easily ignited pyrotechnic that burns rapidly without flashing, suitably a compacted mixture of metal powder and an inorganic oxidizer with or without diluents, binders or other minor components. The ignition core may contain the same material as the candle body, but with a higher amount of metal to give a faster burning rate. Ignition cores may be staged, that is, having portions of different compositions having different burning characteristics. For example, suitable ignition cores may be a compact of from about 20 to 40 percent iron powder, from about 15 to 40 percent sodium chlorate, from about 10 to 20 percent barium peroxide, and from about 5 to 20 percent fiberglas. A variety of ignition core materials are well known and have been used for reliably igniting chlorate candles.
The ignition core is ignited by flash powder 7, that may be any of the well known easily ignitable first-fire pyrotechnic mixtures that, when ignited, burn rapidly to produce a sudden temporary luminous flame. It is preferred to use a mixture of a finely divided metal, such as aluminum, magnesium, titanium, iron or nickel and an inorganic oxidizing agent, for example, alkali metal or alkaline earth metal nitrates, chlorates and perchlorates.
The combustion characteristics of such flash powder mix tures may vary considerably from batch to batch of the same composition because of variations in the materials used that are difficult to detect, define or determine, such as minor variations in size and shape of the particles, particle surface area and condition, and small amounts of impurities. Accordingly, it has been found necessary to run extensive low temperature performance tests on completely assembled oxygen candles to assure that individual batches of flash powder will provide reliable ignition performance.
I have found that reliable candle ignition is obtained over wide variations in flash powder characteristics when a metal screen is positioned between the flash powder and the ignition core. Thus, oxygen candle ignition trains, designed according to conventional practice for particular configurations and compositions, can be made to accommodate wide manufacturing tolerances in flash powder without a high rejection rate of candles.
To illustrate the effectiveness of this invention, a high unpredictable rejection rate for a particular lot of flash powder was experienced when using oxygen candles without screen 12, but otherwise as shown in FIGS. 1 and 2. Flash powder 7 was from a single lot of a mixture of 30 percent nickel, 20 percent titanium, 45 percent potassium perchlorate and 5 percent infusioral earth. The ignition core composition was 30 percent iron, 30 percent sodium chlorate, 25 percent fiberglas and 15 percent barium peroxide. In firing tests made at -30 C., four candles failed completely to ignite and I4 candles generated less than one-half liter of oxygen in the first 15 seconds after ignition, a substandard amount. In the entire 80 tests, the amount of oxygen generated in the first l5 seconds after firing ranged from 0 to 1.1 liters with an average of 0.67 liters.
In 73 tests of the candles of FIGS. 1 and 2, including a 14- mesh screen of 0.02-inch-diameter brass wire and using all materials identical to those in the previously described tests, there were no ignition failures at 30 C. and the oxygen generated in the first 15 seconds after firing ranged from 0.9 to 1.4 liters with an average of l.ll liters.
Although the exact mechanism by which this invention provides improved ignition is not known, it is believed the screen serves to disperse the effective area of the flame from the flash powder, prevents ignition core material from disengaging from the candle body, the core may shrink or become partially molten, and acts as a heat sink. It will be recognized that this invention will be advantageous in any oxygen candle ignition train in which an ignition core is ignited by a flash powder.
I claim:
IOIOO? 0064 1. An oxygen candle comprising a body of material that produces oxygen on burning and a core of ignition material having an ignitable face, a recess in said candle having an end wall comprising said ignitable face, a metal screen covering and abutting said end wall, cover means closing said recess to form a chamber and supporting a body of flash powder within the chamber spaced from said screen, and means to ignite the flash powder from outside said chamber.
2. An oxygen-producing candle according to claim 1 in 0 which said end wall comprises an annular surface of said oxygen producing material.
3. An oxygen-producing candle according to claim 1 in which said cover means engages said screen.
4. An oxygen candle according to claim 3 in which said cover means comprises an inwardly extending tubular conduit engaging said screen, said conduit being partially filled with flash powder.

Claims (3)

  1. 2. An oxygen-producing candle according to claim 1 in which said end wall comprises an annular surface of said oxygen producing material.
  2. 3. An oxygen-producing candle according to claim 1 in which said cover means engages said screen.
  3. 4. An oxygen candle according to claim 3 in which said cover means comprises an inwardly extending tubular conduit engaging said screen, said conduit being partially filled with flash powder.
US884221A 1969-12-11 1969-12-11 Oxygen-producing candle Expired - Lifetime US3615251A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3868225A (en) * 1973-05-25 1975-02-25 Safety Lab Inc Sodium chlorate oxygen producing apparatus
US4623520A (en) * 1984-01-23 1986-11-18 Etablissements Ruggieri Chemical oxygen generator with a low content of impurities
US5376352A (en) * 1993-10-05 1994-12-27 The Penn State Research Foundation Oxygen storage and retrieval system
WO1996038376A1 (en) * 1995-06-01 1996-12-05 Figgie International Inc. Chemical gas generator
US20040151639A1 (en) * 2001-06-07 2004-08-05 David Jones Oxygen generator
US20110140038A1 (en) * 2009-11-17 2011-06-16 Kenneth Lee Presley Oxygen-generating liquid composition
US9090466B2 (en) 2009-11-17 2015-07-28 Api Engineering, Llc Oxygen storage and generation using an oxygen generating liquid

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2764475A (en) * 1953-09-18 1956-09-25 Mine Safety Appliances Co Oxygen generating candle and method of making it
US3377956A (en) * 1965-10-22 1968-04-16 Susquehanna Corp Gas-generating grain

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2764475A (en) * 1953-09-18 1956-09-25 Mine Safety Appliances Co Oxygen generating candle and method of making it
US3377956A (en) * 1965-10-22 1968-04-16 Susquehanna Corp Gas-generating grain

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3868225A (en) * 1973-05-25 1975-02-25 Safety Lab Inc Sodium chlorate oxygen producing apparatus
US4623520A (en) * 1984-01-23 1986-11-18 Etablissements Ruggieri Chemical oxygen generator with a low content of impurities
US5376352A (en) * 1993-10-05 1994-12-27 The Penn State Research Foundation Oxygen storage and retrieval system
WO1996038376A1 (en) * 1995-06-01 1996-12-05 Figgie International Inc. Chemical gas generator
GB2316070A (en) * 1995-06-01 1998-02-18 Figgie Int Inc Chemical gas generator
US5772976A (en) * 1995-06-01 1998-06-30 Figgie International Inc. Chemical gas generator
GB2316070B (en) * 1995-06-01 1999-12-08 Figgie Int Inc Chemical gas generator
US6099806A (en) * 1995-06-01 2000-08-08 Scott Technologies, Inc. Chemical gas generator
US20040151639A1 (en) * 2001-06-07 2004-08-05 David Jones Oxygen generator
US7371350B2 (en) 2001-06-07 2008-05-13 Molecular Oxygen Limited Oxygen generator
US20110140038A1 (en) * 2009-11-17 2011-06-16 Kenneth Lee Presley Oxygen-generating liquid composition
US9090466B2 (en) 2009-11-17 2015-07-28 Api Engineering, Llc Oxygen storage and generation using an oxygen generating liquid

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JPS4929429B1 (en) 1974-08-03
DE2059897A1 (en) 1971-06-24

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