US20090314397A1 - Production of pyrotechnic delay composition - Google Patents
Production of pyrotechnic delay composition Download PDFInfo
- Publication number
- US20090314397A1 US20090314397A1 US12/442,108 US44210807A US2009314397A1 US 20090314397 A1 US20090314397 A1 US 20090314397A1 US 44210807 A US44210807 A US 44210807A US 2009314397 A1 US2009314397 A1 US 2009314397A1
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- United States
- Prior art keywords
- rheology modifier
- process according
- oxidizer
- fuel
- delay composition
- Prior art date
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- 239000000203 mixture Substances 0.000 title claims abstract description 63
- 238000004519 manufacturing process Methods 0.000 title description 8
- 239000007800 oxidant agent Substances 0.000 claims abstract description 28
- 239000004094 surface-active agent Substances 0.000 claims abstract description 28
- 239000000446 fuel Substances 0.000 claims abstract description 25
- 239000002002 slurry Substances 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 20
- 239000007787 solid Substances 0.000 claims abstract description 13
- 239000007788 liquid Substances 0.000 claims abstract description 12
- 239000000047 product Substances 0.000 claims abstract description 8
- 239000012265 solid product Substances 0.000 claims abstract description 6
- 239000002245 particle Substances 0.000 claims description 23
- 239000006254 rheological additive Substances 0.000 claims description 16
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 claims description 14
- 239000000470 constituent Substances 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 239000004927 clay Substances 0.000 claims description 5
- 229910021647 smectite Inorganic materials 0.000 claims description 5
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 3
- AXZAYXJCENRGIM-UHFFFAOYSA-J dipotassium;tetrabromoplatinum(2-) Chemical compound [K+].[K+].[Br-].[Br-].[Br-].[Br-].[Pt+2] AXZAYXJCENRGIM-UHFFFAOYSA-J 0.000 claims description 3
- 239000006185 dispersion Substances 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 239000011777 magnesium Substances 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 3
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 3
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 3
- 229910001487 potassium perchlorate Inorganic materials 0.000 claims description 3
- 238000009877 rendering Methods 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 229910052725 zinc Inorganic materials 0.000 claims description 3
- 239000011701 zinc Substances 0.000 claims description 3
- 239000002202 Polyethylene glycol Substances 0.000 claims 2
- 229920001223 polyethylene glycol Polymers 0.000 claims 2
- 239000003960 organic solvent Substances 0.000 claims 1
- IYLLULUTZPKQBW-UHFFFAOYSA-N Acrinol Chemical compound CC(O)C(O)=O.C1=C(N)C=CC2=C(N)C3=CC(OCC)=CC=C3N=C21 IYLLULUTZPKQBW-UHFFFAOYSA-N 0.000 description 4
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 4
- 239000011856 silicon-based particle Substances 0.000 description 4
- 239000002562 thickening agent Substances 0.000 description 4
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 3
- 238000001694 spray drying Methods 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- -1 acrylic ester Chemical class 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 230000000977 initiatory effect Effects 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000000518 rheometry Methods 0.000 description 2
- 239000000080 wetting agent Substances 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000003945 anionic surfactant Substances 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 239000003093 cationic surfactant Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
- C06C5/00—Fuses, e.g. fuse cords
- C06C5/06—Fuse igniting means; Fuse connectors
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P35/00—Antineoplastic agents
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
- C06B21/0033—Shaping the mixture
- C06B21/0066—Shaping the mixture by granulation, e.g. flaking
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B33/00—Compositions containing particulate metal, alloy, boron, silicon, selenium or tellurium with at least one oxygen supplying material which is either a metal oxide or a salt, organic or inorganic, capable of yielding a metal oxide
Definitions
- THIS INVENTION relates to the production of a pyrotechnic delay composition of the type used, for example, in delay elements employed for the delayed initiation of explosives. More particularly, the invention relates to a process for the production of such composition, and to a pyrotechnic delay composition.
- a process for producing a pyrotechnic delay composition including
- the pyrotechnic delay composition when used in the manufacture of delay elements employed for the delayed initiation of explosives, provides the delay elements with a desired burning rate.
- the liquid may be an organic liquid such as a solvent. Instead the liquid may be water.
- oxidizer and fuel constituents are selected in accordance with practical and economic considerations, bearing in mind safety and the intended use of the delay compositions.
- the oxidizer may be in solid particulate form.
- the oxidizer may comprise red lead, barium sulphate and/or potassium perchlorate.
- the oxidizer may comprise 40-90% by mass of the composition.
- the fuel may also be in solid particulate form.
- the fuel may comprise silicon, zinc and/or magnesium.
- the fuel may comprise 5-60% by mass of the composition.
- the surfactant or surface active agent may be in particulate form, and may be a wetting agent and/or a rheology modifier and/or a binder (binding agent).
- the surfactant may be selected from the so-called non-ionic surfactants, anionic surfactants and cationic surfactants.
- the surfactant may thus comprise an acrylic ester, a styrene polymer, and/or an acylic copolymer, which are all wetting agents; and/or a polyethelene glycol, a powdered smectite clay, carboxymethyl cellulose, polyvinyl alcohol and/or polyvinyl pyrrolidone which are rheology modifiers or thickeners.
- the surfactant may be in the form of an aqueous dispersion when admixed with the oxidizer and the fuel.
- the surfactant may comprise 0.25% to 4%, by mass, of the paste or slurry before drying, i.e. on a wet basis.
- the surfactant may comprise 0.1% to 2%, by mass, of the paste or slurry.
- At least one of the surfactants used may function, in the paste or slurry, as a rheology modifier such as a thickening agent.
- a rheology modifier such as a thickening agent.
- Such rheology modifiers will typically be selected for their ability, not only to alter or modify the burning rate of delay elements made from the delay compositions in question, but also to resist so-called sedimentation or separation of the constituents of the paste or slurry, after formulation thereof and before the drying.
- the surfactant may comprise 0.1-2% by mass of the composition.
- the composition may comprise
- the mixing of the constituents to formulate the paste or slurry will be carried out in a more or less conventional manner, using conventional plant or equipment such as Z blade or high shear mixers, the surfactant or surfactants being added at a convenient time and in the required proportions, to become homogeneously dispersed in the paste or slurry. It is contemplated that two or more surfactants may be employed together, suitable surfactant mixtures thus being used when desired.
- drying of the paste or slurry, rendering of the solid product into particulate form, and classifying the solid particulate product may be carried out in more-or-less conventional manner.
- drying of the paste or slurry in an oven, and hand granulation eg forcing the material through a screen
- spray drying of the slurry whereby the slurry is pumped through an orifice in a two fluid nozzle while simultaneously passing compressed air through the nozzle, to atomize the slurry into droplets, with the resultant droplets being dried by means of hot air, thereby to obtain more-or-less spherical product particles, may be employed.
- burning rates of delay elements made from delay compositions are controlled or modified by altering the particle size and/or the oxidizer:fuel mass ratio in the mixture.
- the oxidizer:fuel ratio has upper and lower limits, beyond which the compositions can no longer reliably sustain combustion. It is thus a feature of the present invention that its technique for controlling burning rates avoids or reduces these problems.
- the invention extends also to a pyrotechnic delay composition when produced in accordance with the first aspect of the invention.
- a pyrotechnic delay composition which is in solid, particulate form, with the particles comprising an oxidizer, a fuel and a surfactant.
- the oxidizer, fuel and surfactant may be as hereinbefore described.
- the delay composition may comprise, on a mass basis,
- Pyrotechnic delay compositions in accordance with the invention, were formulated having the following compositions (proportions expressed as % by mass):
- the pyrotechnic delay compositions were produced as follows: The oxidizers, fuel and surfactant were mixed by hand or by using a high shear mixer, together with sufficient water, to obtain a slurry; the slurry was then oven dried to a consistency that allowed hand granulation by pushing the dried product through a 1 mm screen; thereafter, the resultant granules were further oven dried to reduce the water content to less than 1%, by mass.
- Solsperse 20000 is manufactured by Avecia, and distributed in South Africa by Lubrisol.
- composition comprising 1% Solsperse 20000 and 54% red lead had a burning rate of 19 milliseconds/mm in 3.6 mm inner diameter aluminum tubes, whereas, for the composition comprising 2% Solsperse 20000 and 53% red lead the burning rate decreased to a value of 80 milliseconds/mm.
- Pyrotechnic delay compositions in accordance with the invention, were formulated having the following compositions (proportions expressed as % by mass):
- the pyrotechnic delay compositions were produced in the same manner as in Example 1.
- the Acrinol 296D was obtained from BASF SA (Pty) Limited of 852 1 6th Road, Midrand, Gauteng, South Africa.
- composition comprising 1 % Acrinol 296D and 54% red lead had a burning rate of 22 milliseconds/mm in 3.6 mm inner diameter aluminum tubes, whereas, for the composition comprising 4% Acrinol 296D and 51% red lead the burning rate decreased to a value of 55 milliseconds/mm.
- a pyrotechnic time delay composition was prepared (as hereinafter described) having the following composition in terms of solids on a dry basis (proportions expressed as % by mass):
- All four the dry particulate constituents were homogeneously mixed with water to form a slurry in which the water formed 50% by mass, with the solids thus forming 50%.
- the BENTONE®EW was obtained from Carst & Walker (Pty) Limited of Zenith House, 12 Sherborne Road, Parktown, Africa.
- the slurry was pumped, at a low pressure of 10-100kPa, along a feed line and through a 1.5mm or 2 mm diameter orifice of a centrally positioned (in a spray-drying chamber) upwardly directed two fluid spray nozzle (together with compressed air), thereby being atomized and thus formed into droplets, while low pressure air at a temperature of 210° C.
- the dried product was found to comprise acceptably low proportions of both oversize and undersize particles which could be used, without additional classifying, as a pyrotechnic time delay composition in the manufacture of pyrotechnic time delay elements.
- a pyrotechnic time delay composition was prepared (as hereinafter described) having the following composition in terms of solids on a dry basis (proportions expressed as % by mass):
- the pyrotechnic time delay composition was produced in the same manner as that of Example 3.
- the dried product was found to comprise acceptably low proportions of both oversize and undersize particles which could be used, without additional classifying, as a pyrotechnic delay composition in the manufacture of pyrotechnic time delay elements.
- an oxidizer such as red lead is used to import sensitivity into the composition, particularly for compositions having a slow burning rate, e.g. about 210 ms/mm. It has thus unexpectedly been found that, by employing a surfactant in accordance with the invention in the production of a pyrotechnic time delay composition, it is possible to eliminate the use of red lead, which is desirable due to the hazardous nature of red lead, while still obtaining acceptable burning rates.
- the surfactant used is such that little or no gas is generated by the surfactant when the composition burns. Gas generated by the burning surfactant could lead to malfunctioning of a delay element incorporating the composition.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Pharmacology & Pharmacy (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
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Abstract
A process for producing a pyrotechnic delay composition includes admixing an oxidizer, a fuel, a surfactant and a liquid, to form a paste or slurry. The paste or slurry is dried to remove the liquid and to obtain a solid product which, if necessary, is rendered into particulate form. Optionally, the solid particulate product is classified to obtain a pyrotechnic delay composition in particulate form.
Description
- THIS INVENTION relates to the production of a pyrotechnic delay composition of the type used, for example, in delay elements employed for the delayed initiation of explosives. More particularly, the invention relates to a process for the production of such composition, and to a pyrotechnic delay composition.
- According to a first aspect of the invention, there is provided a process for producing a pyrotechnic delay composition, the process including
-
- admixing an oxidizer, a fuel, a surfactant and a liquid, to form a paste or slurry;
- drying the paste or slurry to remove the liquid and to obtain a solid product;
- if necessary, rendering the solid product into particulate form; and
- optionally, classifying the solid particulate product, to obtain a pyrotechnic delay composition in particulate form.
- The pyrotechnic delay composition, when used in the manufacture of delay elements employed for the delayed initiation of explosives, provides the delay elements with a desired burning rate.
- The liquid may be an organic liquid such as a solvent. Instead the liquid may be water.
- Typically, in the manufacture of pyrotechnic delay compositions of the kind in question by a process of the type to which the present invention relates, the exact oxidizer and fuel constituents, their particle sizes and their proportions in the paste or slurry mixture, are selected in accordance with practical and economic considerations, bearing in mind safety and the intended use of the delay compositions.
- The oxidizer may be in solid particulate form. The oxidizer may comprise red lead, barium sulphate and/or potassium perchlorate. The oxidizer may comprise 40-90% by mass of the composition.
- The fuel may also be in solid particulate form. The fuel may comprise silicon, zinc and/or magnesium. The fuel may comprise 5-60% by mass of the composition.
- The surfactant or surface active agent may be in particulate form, and may be a wetting agent and/or a rheology modifier and/or a binder (binding agent). The surfactant may be selected from the so-called non-ionic surfactants, anionic surfactants and cationic surfactants. The surfactant may thus comprise an acrylic ester, a styrene polymer, and/or an acylic copolymer, which are all wetting agents; and/or a polyethelene glycol, a powdered smectite clay, carboxymethyl cellulose, polyvinyl alcohol and/or polyvinyl pyrrolidone which are rheology modifiers or thickeners. The surfactant may be in the form of an aqueous dispersion when admixed with the oxidizer and the fuel. The surfactant may comprise 0.25% to 4%, by mass, of the paste or slurry before drying, i.e. on a wet basis. Typically the surfactant may comprise 0.1% to 2%, by mass, of the paste or slurry.
- In particular, at least one of the surfactants used may function, in the paste or slurry, as a rheology modifier such as a thickening agent. Such rheology modifiers will typically be selected for their ability, not only to alter or modify the burning rate of delay elements made from the delay compositions in question, but also to resist so-called sedimentation or separation of the constituents of the paste or slurry, after formulation thereof and before the drying.
- The surfactant may comprise 0.1-2% by mass of the composition. Thus, the composition may comprise
-
oxidizer 40-90% fuel 5-60% surfactant 0.1-2% - It is expected that the mixing of the constituents to formulate the paste or slurry will be carried out in a more or less conventional manner, using conventional plant or equipment such as Z blade or high shear mixers, the surfactant or surfactants being added at a convenient time and in the required proportions, to become homogeneously dispersed in the paste or slurry. It is contemplated that two or more surfactants may be employed together, suitable surfactant mixtures thus being used when desired.
- Likewise, drying of the paste or slurry, rendering of the solid product into particulate form, and classifying the solid particulate product, may be carried out in more-or-less conventional manner. For example, to obtain the particles, drying of the paste or slurry in an oven, and hand granulation (eg forcing the material through a screen) may be employed. However, in another embodiment of the invention, spray drying of the slurry, whereby the slurry is pumped through an orifice in a two fluid nozzle while simultaneously passing compressed air through the nozzle, to atomize the slurry into droplets, with the resultant droplets being dried by means of hot air, thereby to obtain more-or-less spherical product particles, may be employed.
- Traditionally, burning rates of delay elements made from delay compositions are controlled or modified by altering the particle size and/or the oxidizer:fuel mass ratio in the mixture. However, there is a lower particle size limit, below which control of burning rate by changing particle size becomes problematic and unreliable; and, similarly, the oxidizer:fuel ratio has upper and lower limits, beyond which the compositions can no longer reliably sustain combustion. It is thus a feature of the present invention that its technique for controlling burning rates avoids or reduces these problems.
- The invention extends also to a pyrotechnic delay composition when produced in accordance with the first aspect of the invention.
- According to a second aspect there is provided a pyrotechnic delay composition, which is in solid, particulate form, with the particles comprising an oxidizer, a fuel and a surfactant.
- The oxidizer, fuel and surfactant may be as hereinbefore described.
- As hereinbefore described, the delay composition may comprise, on a mass basis,
-
oxidizer 40-90%; fuel 5-60%; and surfactant 0.1-2%. - The invention will now be described, by way of non-limiting illustrative example, with reference to the following examples.
- Pyrotechnic delay compositions, in accordance with the invention, were formulated having the following compositions (proportions expressed as % by mass):
-
Constituent A B barium sulphate particles (d50 approx. 3 μm) (oxidizer) 38 38 red lead particles (d50 approx. 3 μm) (oxidizer) 54 53 silicon particles (d50 approx. 3 μm) (fuel) 7 7 Solsperse 20000 (100% (ie undiluted) active polymeric 1 2 dispersant) (surfactant) 100% 100% - The pyrotechnic delay compositions were produced as follows: The oxidizers, fuel and surfactant were mixed by hand or by using a high shear mixer, together with sufficient water, to obtain a slurry; the slurry was then oven dried to a consistency that allowed hand granulation by pushing the dried product through a 1 mm screen; thereafter, the resultant granules were further oven dried to reduce the water content to less than 1%, by mass. Solsperse 20000 is manufactured by Avecia, and distributed in South Africa by Lubrisol.
- The composition comprising 1% Solsperse 20000 and 54% red lead had a burning rate of 19 milliseconds/mm in 3.6 mm inner diameter aluminum tubes, whereas, for the composition comprising 2% Solsperse 20000 and 53% red lead the burning rate decreased to a value of 80 milliseconds/mm.
- Pyrotechnic delay compositions, in accordance with the invention, were formulated having the following compositions (proportions expressed as % by mass):
-
Constituent A B barium sulphate particles (d50 approx. 3 μm) (oxidizer) 38 38 red lead particles (d50 approx. 3 μm) (oxidizer) 54 51 silicon particles (d50 approx. 3 μm) (fuel) 7 7 Acrinol 296D (Aqueous dispersion of acrylic ester/styrene 1 4 polymer) (surfactant) 100% 100% - The pyrotechnic delay compositions were produced in the same manner as in Example 1. The Acrinol 296D was obtained from BASF SA (Pty) Limited of 852 1 6th Road, Midrand, Gauteng, South Africa.
- The composition comprising 1 % Acrinol 296D and 54% red lead had a burning rate of 22 milliseconds/mm in 3.6 mm inner diameter aluminum tubes, whereas, for the composition comprising 4% Acrinol 296D and 51% red lead the burning rate decreased to a value of 55 milliseconds/mm.
- A pyrotechnic time delay composition was prepared (as hereinafter described) having the following composition in terms of solids on a dry basis (proportions expressed as % by mass):
-
Constituent % red lead particles (d50 approx. 3 μm) (oxidizer) 38.25 barium sulphate particles (d50 approx. 3 μm) (oxidizer) 54.25 silicon particles (d50 approx. 3 μm) (fuel) 7 smectite clay particles (BENTONE ®EW) (rheology 0.5% modifier/thickener) 100% - All four the dry particulate constituents were homogeneously mixed with water to form a slurry in which the water formed 50% by mass, with the solids thus forming 50%. The BENTONE®EW was obtained from Carst & Walker (Pty) Limited of Zenith House, 12 Sherborne Road, Parktown, Johannesburg, South Africa. The slurry was pumped, at a low pressure of 10-100kPa, along a feed line and through a 1.5mm or 2 mm diameter orifice of a centrally positioned (in a spray-drying chamber) upwardly directed two fluid spray nozzle (together with compressed air), thereby being atomized and thus formed into droplets, while low pressure air at a temperature of 210° C. was fed into the chamber via filters and a heater, by a fan, to dry the droplets. Spray-drying thus took place in the chamber to form more or less spherical dried particles of more-or-less homogeneous composition. These particles had a moisture content of about 0.1% by mass and remained in the chamber for a period of 1-40 seconds. The dried particles were collected through a solids outlet of the camber. The drying air, which issued from the chamber at 80° C. via an air outlet, was cleaned by passing it through a cyclone, a primary bag filter, and two secondary filters. Dried particles were withdrawn from an outlet of the cyclone. Dried fines were removed from the bag filter.
- The dried product was found to comprise acceptably low proportions of both oversize and undersize particles which could be used, without additional classifying, as a pyrotechnic time delay composition in the manufacture of pyrotechnic time delay elements.
- A pyrotechnic time delay composition was prepared (as hereinafter described) having the following composition in terms of solids on a dry basis (proportions expressed as % by mass):
-
Constituent % barium sulphate particles (d50 approx. 3 μm) (oxidizer) 54.75 silicon particles (d50 approx. 3 μm) (fuel) 44.75 smectite clay particles (BENTONE ®EW) (rheology 0.5 modifier/thickener) 100% - The pyrotechnic time delay composition was produced in the same manner as that of Example 3.
- As was the case in Example 3, the dried product was found to comprise acceptably low proportions of both oversize and undersize particles which could be used, without additional classifying, as a pyrotechnic delay composition in the manufacture of pyrotechnic time delay elements.
- Conventionally, in pyrotechnic time delay compositions, an oxidizer such as red lead is used to import sensitivity into the composition, particularly for compositions having a slow burning rate, e.g. about 210 ms/mm. It has thus unexpectedly been found that, by employing a surfactant in accordance with the invention in the production of a pyrotechnic time delay composition, it is possible to eliminate the use of red lead, which is desirable due to the hazardous nature of red lead, while still obtaining acceptable burning rates.
- Furthermore, it is important that the surfactant used is such that little or no gas is generated by the surfactant when the composition burns. Gas generated by the burning surfactant could lead to malfunctioning of a delay element incorporating the composition.
Claims (20)
1. A process for producing a pyrotechnic delay composition, the process including
admixing an oxidizer, a fuel, a liquid and a rheology modifier having the ability to alter or modify the burning rate of a delay element made from the delay composition, to form a paste or slurry;
drying the paste or slurry to remove the liquid and to obtain a solid product;
if necessary, rendering the solid product into particulate form; and
optionally, classifying the solid particulate product, to obtain a pyrotechnic delay composition in particulate form.
2. The process according to claim 1 , wherein the rheology modifier is in particulate form.
3. The process according to claim 2 , wherein the rheology modifier comprises a polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone and/or a powdered smectite clay.
4. The process according to claim 2 , wherein the rheology modifier, when admixed with the other solid constituents, is in the form of an aqueous dispersion.
5. The process according to claim 1 , wherein the rheology modifier comprises 0.25% to 4%, by mass, of the paste or slurry.
6. The process according to claim 5 , wherein the rheology modifier comprises 0.1% to 2%, by mass, of the liquid-containing paste or slurry.
7. The process according to claim 1 , wherein the liquid is an organic solvent.
8. The process according to claim 1 , wherein the liquid is water.
9. The process according to claim 1 , wherein the oxidizer comprises red lead, barium sulphate and/or potassium perchlorate.
10. The process according to claim 1 , wherein the fuel comprises silicon, zinc, and/or magnesium.
11. The process according to claim 1 , wherein the composition comprises, on a mass basis,
oxidizer 40-90%
fuel 5-60%
rheology modifier 0.1-2%
12. A pyrotechnic delay composition, which is in solid particulate form, with the particles comprising an oxidizer, a fuel and a rheology modifier having the ability to alter or modify the burning rate of a delay element made from the delay composition.
13. A pyrotechnic delay composition according to claim 12 , which includes, in addition to the rheology modifier, another surfactant.
14. A pyrotechnic delay composition according to claim 12 , wherein the rheology modifier comprises a polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone and/or a powdered smectite clay.
15. A pyrotechnic delay composition according to claim 12 , wherein the oxidizer comprises red lead, barium sulphate and/or potassium perchlorate.
16. A pyrotechnic delay composition according to claim 12 , wherein the fuel comprises silicon, zinc, and/or magnesium.
17. A pyrotechnic delay composition according to claim 12 , wherein the composition comprises, on a mass basis,
oxidizer 40-90%
fuel 5-60% rheology modifier 0.1-2%
18. A pyrotechnic delay composition according to claim 12 , which contains no red lead.
19. The process according to claim 1 , which includes admixing with the oxidizer and the fuel, another surfactant in addition to the rheology modifier.
20. The process according to claim 1 , wherein the pyrotechnic delay composition contains no red lead.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ZA2006/07884 | 2006-09-20 | ||
ZA200607884 | 2006-09-20 | ||
PCT/IB2007/053781 WO2008035289A2 (en) | 2006-09-20 | 2007-09-19 | Production of pyrotechnic delay composition |
Publications (1)
Publication Number | Publication Date |
---|---|
US20090314397A1 true US20090314397A1 (en) | 2009-12-24 |
Family
ID=39200928
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/442,108 Abandoned US20090314397A1 (en) | 2006-09-20 | 2007-09-19 | Production of pyrotechnic delay composition |
Country Status (13)
Country | Link |
---|---|
US (1) | US20090314397A1 (en) |
EP (1) | EP2064165A2 (en) |
AP (1) | AP2009004805A0 (en) |
AR (1) | AR062924A1 (en) |
AU (1) | AU2007298523A1 (en) |
BR (1) | BRPI0715148A2 (en) |
CA (1) | CA2663955A1 (en) |
CL (1) | CL2007002676A1 (en) |
MA (1) | MA30796B1 (en) |
MX (1) | MX2009003008A (en) |
PE (1) | PE20080530A1 (en) |
WO (1) | WO2008035289A2 (en) |
ZA (1) | ZA200708113B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109503301A (en) * | 2019-01-14 | 2019-03-22 | 湖北航天化学技术研究所 | A kind of hydrocarbon fuel-rich propellant |
CN109574773A (en) * | 2019-01-14 | 2019-04-05 | 湖北航天化学技术研究所 | A kind of boron-based fuel-rich |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3090232B1 (en) * | 2014-01-03 | 2018-03-07 | Dynitec GmbH | Pyrotechnic delay charge for military delay elements |
Citations (5)
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US2560452A (en) * | 1947-06-04 | 1951-07-10 | Canadian Ind | Delay compositions for electric blasting caps |
US2717204A (en) * | 1952-05-02 | 1955-09-06 | Du Pont | Blasting initiator composition |
US3111438A (en) * | 1961-10-24 | 1963-11-19 | Atlas Chem Ind | Delay compositions for delay electric detonators |
US6170399B1 (en) * | 1997-08-30 | 2001-01-09 | Cordant Technologies Inc. | Flares having igniters formed from extrudable igniter compositions |
US6436211B1 (en) * | 2000-07-18 | 2002-08-20 | Autoliv Asp, Inc. | Gas generant manufacture |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
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DE3008001C2 (en) * | 1980-03-01 | 1982-06-03 | Dynamit Nobel Ag, 5210 Troisdorf | Pyrotechnic mixture of sentences for delay elements |
SE460848B (en) * | 1987-09-29 | 1989-11-27 | Bofors Ab | SET TO MAKE PYROTECHNICAL PRE-DRAWING AND RUNNING KITS |
DE3808366A1 (en) * | 1988-03-12 | 1989-10-05 | Dynamit Nobel Ag | DELAY SETS WITH LONG DELAY TIMES |
SE470537B (en) * | 1992-11-27 | 1994-07-25 | Nitro Nobel Ab | Delay kit and elements and detonator containing such kit |
CA2340523C (en) * | 2001-03-09 | 2009-06-02 | Orica Explosives Technology Pty Ltd. | Delay compositions and detonation delay devices utilizing same |
-
2007
- 2007-09-14 CL CL200702676A patent/CL2007002676A1/en unknown
- 2007-09-19 AP AP2009004805A patent/AP2009004805A0/en unknown
- 2007-09-19 CA CA002663955A patent/CA2663955A1/en not_active Abandoned
- 2007-09-19 PE PE2007001261A patent/PE20080530A1/en not_active Application Discontinuation
- 2007-09-19 US US12/442,108 patent/US20090314397A1/en not_active Abandoned
- 2007-09-19 AU AU2007298523A patent/AU2007298523A1/en not_active Abandoned
- 2007-09-19 WO PCT/IB2007/053781 patent/WO2008035289A2/en active Application Filing
- 2007-09-19 BR BRPI0715148-9A patent/BRPI0715148A2/en not_active IP Right Cessation
- 2007-09-19 MX MX2009003008A patent/MX2009003008A/en unknown
- 2007-09-19 EP EP07826439A patent/EP2064165A2/en not_active Withdrawn
- 2007-09-20 ZA ZA200708113A patent/ZA200708113B/en unknown
- 2007-09-20 AR ARP070104165A patent/AR062924A1/en unknown
-
2009
- 2009-04-16 MA MA31792A patent/MA30796B1/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2560452A (en) * | 1947-06-04 | 1951-07-10 | Canadian Ind | Delay compositions for electric blasting caps |
US2717204A (en) * | 1952-05-02 | 1955-09-06 | Du Pont | Blasting initiator composition |
US3111438A (en) * | 1961-10-24 | 1963-11-19 | Atlas Chem Ind | Delay compositions for delay electric detonators |
US6170399B1 (en) * | 1997-08-30 | 2001-01-09 | Cordant Technologies Inc. | Flares having igniters formed from extrudable igniter compositions |
US6436211B1 (en) * | 2000-07-18 | 2002-08-20 | Autoliv Asp, Inc. | Gas generant manufacture |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109503301A (en) * | 2019-01-14 | 2019-03-22 | 湖北航天化学技术研究所 | A kind of hydrocarbon fuel-rich propellant |
CN109574773A (en) * | 2019-01-14 | 2019-04-05 | 湖北航天化学技术研究所 | A kind of boron-based fuel-rich |
Also Published As
Publication number | Publication date |
---|---|
BRPI0715148A2 (en) | 2013-05-28 |
MA30796B1 (en) | 2009-10-01 |
AR062924A1 (en) | 2008-12-17 |
MX2009003008A (en) | 2009-05-11 |
CA2663955A1 (en) | 2008-03-27 |
WO2008035289A2 (en) | 2008-03-27 |
WO2008035289A3 (en) | 2008-12-24 |
PE20080530A1 (en) | 2008-05-30 |
AU2007298523A1 (en) | 2008-03-27 |
WO2008035289A8 (en) | 2008-05-29 |
CL2007002676A1 (en) | 2008-02-22 |
AP2009004805A0 (en) | 2009-04-30 |
AU2007298523A2 (en) | 2009-06-25 |
EP2064165A2 (en) | 2009-06-03 |
ZA200708113B (en) | 2008-10-29 |
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Owner name: AEL MINING SERVICES LIMITED, SOUTH AFRICA Free format text: CHANGE OF NAME;ASSIGNOR:AFRICAN EXPLOSIVES LIMITED;REEL/FRAME:027082/0834 Effective date: 20110314 |
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STCB | Information on status: application discontinuation |
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