US3352238A

US3352238A - Atomizer and method for disseminating toxicants

Info

Publication number: US3352238A
Application number: US495255A
Authority: US
Inventors: Hal R Spragg; Luther A Price; James M Wooldridge
Original assignee: Universal Match Corp
Current assignee: Universal Match Corp
Priority date: 1965-10-12
Filing date: 1965-10-12
Publication date: 1967-11-14
Anticipated expiration: 1984-11-14

Description

Nov. 14, 1967 SPRAGG ET AL 3,352,238

ATOMIZER AND METHOD FOR DISSEMINATING TOXICANTS Filed Oct. 12, 1965 2 Sheets-Sheet 1 INVENTORS R. SPRAGG, ER Av PRICE 5 M. WOOLD'RIDGE ATTORNEYS NOV. 14, 1967 SPRAGG ET AL 3,352,238

ATOMIZER AND METHOD FOR DISSEMINATING TOXICANTS Filed Oct. 12, 1965 2 Sheets-Sheet 2 INVENTORS HAL R. SPRAGG, LUTHER A. PRICE, JAMES M. WOOLDRIDGE ATTORNEYS United States Patent 3,352,238 ATUMEZER AND METHOD FOR DISSEMINATING TOXICANTS Hal R. Spragg and Luther A. Price, Phoenix, and James M. Wooldridge, Glendale, Ariz., assignors to Universal Match Corporation, a corporation of Delaware Filed Oct. 12, 1965, Ser. No. 495,255 8 Claims. (Cl. 102-39) ABSTRACT OF THE DISCLOSURE A pyrotechnic atomizer for normally solid toxicant charges which includes a propellant charge and in which the size of the propellant charge and the atomizer geometry are adapted to provide a relatively high-velocity stream of propellant gases. The propellant gases flow through pilot apertures in the charge and disseminate the toxicant by abrasion of the charge under limited heat-exchange conditions, thereby avoiding vaporization or melting of a substantial part of the toxicant charge.

This invention relates to the dissemination of toxicant agents. In a particular aspect, the invention concerns a novel method of disseminating toxicants and, in another aspect, concerns apparatus for practicing such methods. In a further aspect, the invention particularly concerns the dissemination of toxicants having relatively low heatdecornposition temperatures and methods and apparatus for carrying out the dissemination of such toxicants.

As used herein, the term toxicant is intended to mean and encompass a wide variety of biologically active agents including the so-called economic poisons such as insecticides, fungicides, herbicides and the like, as well as the various irritants and toxicants employed in police and military operations such as so-called tear gases, and war gases, both the non-lethal debilitating agents and the lethal agents such as nerve gases and the like. Of particular interest in connection with the invention are those toxicants having a relatively low heat-decomposition temperature, i.e., substantially below the temperature of gases produced pyrotechnically in the devices and the methods of the prior art.

In the dissemination of toxicants, it is generally required that the toxicant be disseminated in the locus to be treated during a suitably short time period in order to establish the minimum effective concentration of the toxicant in the locus before dispersion eifects come into operation. Additionally, it is required that the bulk of the toxicant be disseminated in a biologically active form, avoiding decomposition of the agent into a less effective or totally ineffective form. Also, practical considerations such as the mobility, cost and reliability of the disseminating apparatus, particularly as influenced by military or police requirements, make it highly desirable that the overall unit weight efiiciency of apparatus used in the dissemination of toxicants be as high as possible. The term overall unit weight efficiency used herein means the percentage relationship of the weight of toxicant actually and effectively disseminated to the total weight of toxicants and associated disseminating hardware, propellants, found in the original disseminating apparatus. The classical overall unit weight 3,352,238 Patented Nov. 14, 1967 efiiciency of the prior art pyrotechnic toxicant disseminators is in the range 10-20 percent, although higher efiiciencies have long been a prime desideratum.

It is an object of the present invention to provide a novel method for disseminating toxicants, particularly those toxicants having a relatively low heat decomposition temperature;

Another object of the invention is the provision of a simple and relatively inexpensive, yet highly effective atomizing device for toXicant-s providing quick dissemination of the toxicant into the locus to be treated;

Another object of the invention is the provision of an atomizing device for toxicants having a relatively much higher overall unit weight efficiency than those found in the prior art;

Yet another object of the invention is the provision of an atomizing device having a high overall unit weight efliciency which is especially adapted to the dissemination of toxicants having relatively low heat decomposition temperatures;

Another object of the invention is the provision of a method of dissemination of toxicants and apparatus useful in the practice of such methods whereby the toXicant is pyrotechnically disseminated by means other than simple vaporization which often causes thermal degradation of a substantial quantity of the toxicant.

Yet another object of the invention is the provision of a pyrotechnic atomizing device for toxicants wherein the pyrotechnic and t-oxicant charges are maintained until actual operation of the device in a sealed integument, thereby minimizing the danger of inadvertent contamination of the surroundings by the toxicant and further minimizing the possibility that the contents will become damaged by external causes.

Other, further and more specific objects of the invention will become readily apparent to persons skilled in the art from a consideration of the following description when taken in conjunction with the drawings and examples wherein specifically preferred embodiments of the invention are shown and exemplified.

FIG. 1 is an external perspective view of a presently preferred embodiment of my invention chosen for purposes of illustration;

FIG. 2 is a cross-sectional view of the device of FIG. 1 taken along section line 22 of FIG. 1;

FIG. 3 is an end-view of the device of FIG, 1 taken along section line 33, the view being partially broken away to show the detail of the fuse assembly;

FIG. 4 is a partial sectional view of the gas-distrubting orifice plate of the device of FIGS. 1-3;

FIG. 5 is a partial sectional perspective view of a gaspermeable toxicant charge element adapted for use in the assembly of FIGS. 1-3

FIG. 6 is a perspective view of the retaining ring which secures the fuse-ignitor assembly of the device of FIGS. 1-3;

FIG. 7 is a perspective view of flame-front-limiting partition screen for use in the device of FIGS. 1-3;

FIG. 8 shows another embodiment of the invention wherein the toxicant charge elements are of a generally elongate cylindrical shape and are positioned in the toxicant chamber of the device as a gas-permeable bundle;

FIG. 9 shows a single cylindrical toxicant charge element of the device of FIG. 8.

In the practice of my invention, a normally solid toxicant composition is disseminated by contacting the composition in an atomizing zone with a stream of carrier gas under gas velocity conditions providing abrading contact between the gas and the composition, thereby to produce an aerosol of the toxicant composition in the carrier gas. In the presently preferred embodiments, the carrier gas is pyrotechnically produced and the toxicant composition is contacted with the relatively high velocity stream of hot pyrotechnically produced gases, the How path of the gases being limited to provide abrading, limited heat exchange conditions of pressure, velocity and contact time, thereby producing the aerosol of the toxicant in the pyrotechnically produced carrier gas without degrading a substantial portion of the toxicant material. Manifestly, the methods of the invention are advantageously employed in connection with the dissemination of toxicants having a relatively low thermal decomposition temperature. The pyrotechnic gases are produced by firing a propellant charge in a gas-generating zone, the flame front thus produced being physically segregated from the toxicant charge, suitably by means of a flamefront-limiting screen or other equivalent means. The path of expansion of the hot propellant gases produced in the gas-generating zone is limited to provide a relatively high velocity stream which is directed through a toxicant charge which is gas-permeably disposed in an atomizing zone. By suitable selection of conditions of pressure velocity and contact time, the contact between the propellant gas and the toxicant charge can be adjusted to provide abrading but limited heat-exchange conditions. Thus, the toxicant is aerosolized in the carrier gases without raising the temperature of a substantial portion of the toxicant to its decomposition temperature.

According to another aspect of the invention, 1 provide apparatus especially adapted to disseminate toxicants according to the methods hereabove disclosed. Briefly, the apparatus comprises a pyrotechnic gas-generating propellant charge, a toxicant charge and a casing enclosing said charges. The casing is divided by a fiame-front-limiting partition into a gas-generating chamber containing the propellant charge and an atomizing chamber containing the toxicant charge. The toxicant charge is positioned within the atomizing chamber in the path of gases generated by firing the propellant charge. The casing and the propellant and toxicant charges are dimensioned to provide abrading, limited heat exchange contact between the propellant gas and the toxicant when the propellant is fired, thereby to aerosolize the toxicant without raising the temperature of a substantial portion thereof to its decomposition temperature.

Turning now to the drawings inw hich presently preferred embodiments of the apparatus of the invention are depicted for purposes of illustration, FIG. 1 is an external perspective view of such device showing the generally elongate casing 1 which encloses the propellant and toxicant charges. The igniting assembly comprises a fuse 2 which ignites an initiating charge secured to the casing by means of a foil cover 3 and a retaining strap 4. Upon the ignition of the propellant charge, the aerosolized toxicant issues from the discharge end of the casing, generally indicated by the reference numeral 5, through a screen assembly 6.

FIG. 2 is a cross-sectional view of the device of FIG. 1. The casing 1 is constructed of relatively thin, lightweight metal or other suitable materials such as plastics, cardboard and the like. The propellant charge 11 is positioned in a closed end of the casing, the closure being effected by crimping the end of the casing (indicated by reference numeral 12) over a disc-shaped end member 13' thereby to provide a substantially gas-tight closure. The ignitor charge 14 is disposed against the exterior of the end member 13, within the cavity formed by the crimped end of the tubing and the end member. A springloaded clip 15, spot welded to the end member 13, holds the fuse 2 in position to fire the igniting charge 14. When the igniting charge 14 is fired, the end member 13 is heated thereby and, in turn, the heated end member 13 ignites the main propellant charge 11. This so-called through bulkhead ignition, while not necessary to the operation of the apparatus of the invention, is convenient and advantageous in that it permits the main propellant charge to be completely enclosed by a gastight casing and obviates providing holes in the casing to permit the insertion of ignition wires or fuses, The igniting charge 14 and the fuse 2 are secured to the casing and positioned in heat-exchange relation with the main propellant charge by means of the foil cover 3 and the retaining strap 4 which encircles the casing below the shoulder formed by the crimped end of the casing 12. The propellant charge 11 is physically segregated from the toxicant charge elements 16 by means of screens 17 which divide the easing into a gas-generating zone containing the propellant charge 11 and an atomizing zone containing the toxicant charges 16. The screens 17 limit the flame front produced by the propellant charge 11 and direct the gaseous products of the combustion of the propellant charge through the charge elements 16. These charge elements are separated by screens 18 which assist in positioning the toxicant charge elements in gas-permeable relation to the propellant gases flowing therethrough. The pressure within the casing during operation of the device is maintained and controlled by means of an orifice and distributing plate 19 positioned and retained in the discharge end of the casing by means of the cap member 20. Prior to firing, the contents of the casing are protected by a seal 20a of suitable membrane-like plastic or equivalent material which ruptures or releases when the device is fired, thereby permitting dissemination of the toxicant aerosol into the locus of the device.

FIG. 3 is a partially broken away end view of the device of FIG. 1 showing the crimped end of the casing, the fuse 2, the fuse retaining clip 15 and the foil cover 3.

FIG. 4 shows a suitable pressure-regulating and gasdistributing orifice plate for use in the device of FIG. 1. The general direction of the gas flow through the orifice plate is shown by the arrow 41. The plate is drilled as shown to provide radial ducts 42 communicating between the relatively large central aperture 43 and the periphery of the orifice plate. A series of longitudinal ducts 44 are drilled in the upstream side of the plate. These longitudinal ducts communicate with the radial ducts 42. The orifice plate, drilled as shown in FIG. 4, provides for even distribution of the gas flow across the cross-sectional area of the casing.

FIG. 5 is a partial sectional view of the gas-permeable charge elements shown in cross-section in FIG. 2. These charge elements are generally cylindrically shaped and provided with a plurality of longitudinal pilot holes 51 through which the propellant gases pass when the device is fired. Of course, as the toxicant charge is abraded, the holes are gradually enlarged until essentially the entire charge element has been disseminated.

FIG. 6 is a detailed view of the retaining strap which secures and positions the foil and fuse on the normally closed end of the casing. The strap is generally circular as shown and is provided with a recessed portion 61 which receives the fuse when the strap is mounted upon the casing of the device of FIG. 1. The strap is secured by means of a tab 62 which engages the slot 63 and is then bent backwardly as shown in FIG. 1.

A variety of toxicant charge shapes are possible, the principal requirement being gas permeability when positioned in the atomizing chamber. For example, as shown in FIG. 9, the solid toxicant charges can be shaped as elongate cylinders 81 which can be packed in a generally cylindrical bundle for placement in the atomizing chamher.

In the dissemination of toxicants having relatively low thermal decomposition temperatures in accordance with the invention, it is necessary to adjust the pressure-temperature-contact time conditions in the atomizing zone to provide abrading, limited heat-exhange conditions. The term limited heat exchange, as used herein, is intended to depict conditions whereby substantially all of the toxicant charge is disseminated by the formation of an aerosol through incipient melting and abrasion of the solid charge by the relatively high velocity carrier gas stream passing through the atomizing zone. It is believed that the minor portion of the toxicant charge which is actually vaporized by the hot gases provides a transient thermal insulation for the bulk of the toxicant charge according to the well-known leydenfrost shielding phenomenon.

second. It is possible to employ somewhat higher gas velocities (and correspondingly shorter contact times) but this generally requires increased internal pressure, making it necessary to employ heavier casing material. Lower gas velocities (and correspondingly longer contact times) will be only partially eflective, especially when the toxicant is easily thermally degraded.

Among the toxicants which can be successfully disseminated in accordance with the methods and apparatus herein disclosed may be mentioned CS, CN, DM, HD (mustard gas), Sarin, Tabun, and other organophosphorus or similar compounds including structurally related compounds. In addition, it is feasible to disseminate insecticides such as DDT, TEPP and Chlordane as well as The present invention contemplates the use of pressures various dye stuffs for the production of smokes such as in the atomization zone which are notably low, e.g., 1-methylaminoanthraquinone; 1,4-diamino-2,3 dihydro- 5-100 p.s.i., especially about -50 p.s.i. The pressure anthraquinone; 1,9-benz-l0-anthr0ne; 1,4-di toluidinowithin the devices of the invention can be suitably conanthraquinone and HC. Transcinnamic acid and 2,4-dihytrolled by the adjustment of the number, placement and droxybenzophenone, compounds which have very low size of the ducts and apertures in the orifice plate as 20 thermal decomposition temperat have been successshown in the drawings. fully disseminated by the devices and methods herein dis- The temperature conditions encountered in the atomizclosed even though propellants with flame temperatures ing zone can be controlled by the selection of a propellant as high as 3000 K. were employed. Toxicants such as having a suitable burning temperature. The prime re- Tabun and HD (mustard gas) also have relatively low quirement of the propellant is that it provide suflicient decomposition temperatures (130 C. and 150180 0., thermal and kinetic energy to disseminate the toxicant. respectively). Toxicants such as DM and CN are table However, it is also desired that the mildest possible temup to their boiling points (410 C. and 245 C., respecperature conditions be maintained in the atomizing zone. y)-

To this end, it is generally desired to select a propellant n general, the ratio of the weight of propellant to having the highest possible flame temperature, gas release Weight of toxicant employed according to the invention and burning rate characteristics consistent with maintainill vary from about 0.5 to about 5, depending on the ing suitably low temperature conditions in the atomizing specific toXicant compounds and propellants involved. Of zone to prevent thermal degradation of the particular Course, propellant must be selected hich Will provide toxicant material. As representative of the various types of Combustion Products Which are Chemically Compatible propellants which may be employed to disseminate vari- With the toxicant compound. ous toxicants may be mentioned the so-called cool According to another embodiment of the invention, a b i ll t h as th various ammonium iblowing agent is incorporated in the toxicant charge eletrate compositions, guanidine nitrate propellants, the so- Ineht to Promote the abrasion y the stream f Carrier called mono propellants such as hydrazine nitro A typieal blowing agent which is successfully emmethane, lower alkyl nitrates, H 0 and the like, and P y in this manner is ,7 tetra-azobigasless heat sources such as thermite-type compositions in Y l 21 a ion conjunction with volatile diluents such as water, etc. These 0f the toxicant Charge is also Promoted y P g a cool burning propellants generally produce flame temstream of abrading carrier gas containing solid particles. peratures of not greater than about 2000 K. On the For example, such carrier gases may be produced by other hand, depending on the particular toxicant to be burning a metal fuel-oxidizer mix in the propellant chamdisseminated, it is possible to employ a propellant having her such as an aluminum-potassium perchlorate mix r a somewhat higher flame temperature, such as the single a mix comprising a double base propellant of the RDX- B (flame temperathfe 30000 K'): the so-eahed type and a finely divided silica such as that commercially double ba se propellantshavmg a flame temperature of avaiiabie under the tradename 2200*2800 composlte PEOPeHantS, In another embodiment of the invention, a liquid tox- (fiame temperature 19003500 K.), RDX-type propelicant can be dis ensedb b1 .4 lants (flame temperature 2500-3000" K.) RDX double P mg 1 ."f a 5mm 6 form for pos1t1on1n within the atomizm chamber s base propellants (flame temperature 3300 K.). h D a m h device f the invention and the area t e case of a normally SOlld toxicant. Th s can be accomcasmg of t e pllshed by distributing the liquid toxicant through a available for gas flow through the gas-permeable toxicant Orous Wafer f the i fi h FI charge elements should be sized to provide contact times 2 o genera gun} Ion S own In between the carrier gas and the toxicant charge elements or by encapsulatmg hqmd. toxlcanl and the]? mix- Which are sufliciently short to minimize the thermal dethe lncapsualted toxlcant with a s,u1tab1e Sohd composition of the toxicant during formation of the tenal whlch can be than Shaped as deslredaerosol. For example, it has been found that calculated 6O EXAMPLE gas velocities in the range of from about to about 100 feet per second at the discharge end of the disseminating To demonstrate the principles of the invention, several device of the drawings will produce satisfactory results. devices of the configuration Shown ill FIGS- 0f the Velocities in this range provide calculated contact times drawings Were assembled and tested With the s l s in the atomizing zone in the order of a fraction of a shown in Table 1 below. In each test the casing was fab- TABLE I Propellant Toxicant Overall Unit Test Weight T p Weight, g. Type Weight, g. Percent RDXdouble base 12.7 O 16.6 30 SR4990 30.1 C8 67.7 34 SR 4990 30.2 l-methylamino 54.7 29

anthraquinone.

ricated of .026 mm. thick steel tubing having an internal diameter of 24 mm. The propellants were selected to provide a gas velocity through the atomizing zone in the range of 60 100 f.p.s. which was calculated from the volumetric gas yield of the propellant, the burning rate and the open cross-sectional area of the orifice plate. Exit gas temperatures ranged from ISO-300 C. The orifice plates were drilled to provide an internal gas pressure of from 2050 p.s.i. So-called hot burning propellants were deliberately selected in order to demonstrate that toxicants having low heat decomposition temperatures could nevertheless be effectively disseminated by proper adjustment of contact time, pressure and gas velocity conditions to provide abrading, limited heat exchange conditions in the atomizing zone.

The aerosols thus produced were collected in an absorption column. Infrared analysis for structure and ultraviolet and spectrophotometric analyses for quantities confirmed that there was no substantial thermal degradation of the toxicant charge during dissemination.

My invention has been described particularly with reference to the presently preferred embodiment thereof chosen for purposes of illustration. However, it is not intended to indicate that the scope of the invention is limited to the particularly preferred embodiments shown and described but, rather, only by a just interpretation of the following claims.

I claim:

1. A pyrotechnic atomizer for toxicants comprising: a pyrotechnic gas-generating propellant charge; a normally solid toxicant charge element having longitudinal pilot apertures therein, providing an initial conduit for propellant gases flowing therethrough, which apertures are enlarged by abrasion of the charge element by said gases until essentially the entire charge element is consumed; a casing for said propellant and toxicant charges; a flamefront-limiting partition dividing said easing into a gasgenerating chamber containing said propellant charge and an atomizing chamber containing said toxicant charge positioned therewithin to provide abrading, limited heatexchange contact between the propellant gas and the normally solid toxicant charge element to aerosolize said toxicant charge when said propellant is fired without raising the temperature of a substantial portion of said toxicant to its decomposition temperature.

2. A pyrotechnic atomizer especially adapted to aerosolize a toxicant having a relatively low decomposition temperature comprising: a pyrotechnic gas-generating propellant charge; a normally solid toxicant charge element having longitudinal pilot apertures therein, providing an initial conduit for propellant gases flowing therethrough, which apertures are enlarged by abrasion of the charge element by said gases until essentially the entire charge element is consumed; a generally elongate casing for said propellant and toxicant charges; a fiamefrontlimiting partition screen dividing said easing into a gasgenerating chamber containing said propellant charge and an atomizing chamber containing said toxicant charge gas-permeably positioned therewithin to provide abrading, limited heat-exchange contact between the propellant gas and the normally solid toxicant charge element to aerosolize said toxicant charge when said propellant is fired without raising the temperature of a substantial portion of said toxicant to its decomposition temperature.

3. A pyrotechnic atomizer especially adapted to aerosolize a toxicant having a relatively low decomposition temperature comprising: a pyrotechnic gas-generating propellant charge having a relatively low burning temperature; a toxicant charge comprising a plurality of shaped normally solid charge elements having longitudinal pilot apertures therein, providing an initial conduit for propellant gases flowing therethrough, which apertures are enlarged by abrasion of the charge elements by said gases until essentially the entire charge elements are consumed; a generally elongate thin-walled casing for said propellant and toxicant charges; a flamefront-limiting partition dividing said easing into a gas-generating chamber containing said propellant charge and an atomizing chamber containing said toxicant charge elements gas-permeably positioned therewithin providing abrading, limited heat-exchange contact between the propellant gas and the normally solid toxicant charge elements to aerosolize said toxicant charge when said propellant is fired without raising the temperature of a substantial por-- tion of said toxicant to its decomposition temperature.

4. A pyrotechnic atomizer especially adapted to aerosolize a toxicant having a relatively low decomposition temperature comprising: a pyrotechnic gas-generating propellant charge; a plurality of toxicant charge elements having longitudinal pilot apertures therein, providing an initial conduit for propellant gases flowing therethrough, which apertures are enlarged by abrasion of the charge elements by said gases until essentially the entire charge elements are consumed; a casing for said propellant and toxicant charges; a fiamefront-limiting partition dividing said easing into a gas-generating chamber containing said propellant charge and an atomizing chamber containing said toxicant charges gaspermeably positioned at spaced points therewithin; gas flow directing members positioned between said toxicant charges in said atomizing chamber and adapted to direct propellant gas flowing therethrough into abrading, limited heat-exchange contact with said normally solid toxicant charge elements to aerosolize said toxicant charges when said propellant is fired without raising the temperature of a substantial portion of said toxicant to its decomposition temperature.

5. A pyrotechnic atomizer especially adapted to aerosolize toxicants having a low thermal decomposition temperature comprising: a pyrotechnic gas-generating propellant charge having a relatively low burning temperature; a normally solid toxicant charge comprising a plurality of charge elements having longitudinal pilot apertures therein, providing an initial conduit for propellant gases flowing therethrough, which apertures are enlarged by abrasion of the charge elements by said gases until essentially the entire charge elements are consumed; a thin-walled generally elongate cylindrical casing for said propellant and toxicant charges, said casing having one closed end and one releasably sealed end; a flamefrontlimiting partition screen dividing said easing into a gasgenerating chamber generally located in the closed end of said casing containing said propellant charge and an atomizing chamber generally located in the releasably sealed end of said casing containing said normally solid toxicant charge elements positioned therewithin to provide abrading, limited heat-exchange contact between the propellant gas and the toxicant to aerosolize said toxicant charge when said propellant is fired without raising the temperature of a substantial portion of said toxicant to its decomposition temperature; an igniter disposed in heat-exchange relation to said propellant charge; releasably sealing means associated with said releasably sealed end adapted to release when said propellant is initiated.

6. The method of disseminating a toxicant composition comprising providing a relatively high-velocity stream of carrier gases, contacting said carrier gas with a normally solid toxicant charge element having longitudinal pilot apertures therein, providing an initial conduit for said carrier gases flowing therethrough, which apertures are enlarged by the abrasion of the charge element by said gases until essentially the entire charge element is consumed, said contacting being carried out under gas velocity conditions providing abrading contact between said gas and said composition to produce an aerosol of said toxicant in said carrier gas, and discharging said resulting aerosol from said atomizing zone.

7. The method of pyrotechnically disseminating a normally solid toxicant composition comprising providing a relatively high-velocity stream of pyrotechnically produced propellant gases; contacting said propellant gases with a normally solid charge element of said toxicant composition having longitudinal pilot apertures therein, providing an initial conduit for propellant gases flowing therethrough, which apertures are enlarged by abrasion of the charge element by said gases until essentially the entire charge element is consumed, said contacting being carried out in an atomizing zone under abrading, limited heat exchange conditions of pressure, velocity and contact time to produce an aerosol of said toxicant in said gases; and discharging said aerosol from said atomizing zone.

8. The method of pyrotechnically disseminating an aerosol of a toxicant having a relatively low thermal decomposition temperature comprising igniting a pyrotechnic gas-generating propellant charge in a gas-generating zone wherein the flamefront thus produced is physically segregated from the toxicant; limiting the path of eX- pansion of the propellant gases produced in said gas-generating zone to provide a relatively high velocity stream of said gases, directing said high velocity stream of gases through a normally solid toxicant charge element having longitudinal pilot apertures therein, providing an initial conduit for propellant gases flowing therethrough, which apertures are enlarged by abrasion of the charge element by said gases until essentially the entire charge element is consumed, said propellant gases contacting said toxicant charge in an atomizing zone under abrading, limited heatexchange conditions of pressure, velocity and contact time to provide an aerosol of said toxicant in said gases without raising the temperature of a substantial portion of said toxicant to its decomposition temperature; and discharging said aerosol from said atomizing zone.

References Cited UNITED STATES PATENTS 2,603,607 7/1952 Stevenson 10290 X 3,109,821 11/1963 York et al. 102--90X BENJAMIN A. BORCHELT, Primary Examiner.

ROBERT F. STAHL, Examiner.

Claims

1. A PYROTECHNIC ATOMIZER FOR TOXICANTS COMPRISING: A PYROTECHNIC GAS-GENERATING PROPELLANT CHARGE; A NORMALLY SOLID TOXICANT CHARGE ELEMENT HAVING LONGITUDINAL PILOT APERTURES THEREIN, PROVIDING AN INITIAL CONDUIT FOR PROPELLANT GASES FLOWING THERETHROUGH, WHICH APERTURES ARE ENLARGED BY ABRASION OF THE CHARGE ELEMENT BY SAID GASES UNTIL ESSENTIALLY THE ENTIRE CHARGE ELEMENT IS CONSUMED; A CASING FOR SAID PROPELLANT AND TOXICANT CHARGES; A FLAMEFRONT-LIMITING PARTITION DIVIDING SAID CASIGN INTO A GASGENERATING CHAMBER CONTAINING SAID PROPELLANT CHARGE AND AN ATOMIZING CHAMBER CONTAINING SAID TOXICANT CHARGE