US1448073A - Production and utilization of smoke-producing compositions - Google Patents

Description

Mar. 13, 1923. 1,448,073

' o. D. LUCAS ET AL PRODUCTION AND UTILIZATION OF SMOKE PRODUCING COMPOSITIONS Filed May 24, 1922 5 i i i i a ai i i i i ill ii?! Patented Mar. 13, 1923.

UN'll STATES OWEN DAVID LUCAS, OF BAYSWATER, LONDON, AND FREDERICK GEOFFREY LEES JOHNSON, OF WESTMINSTER, LONDON, ENGLAND, ASSIGNORS TO VICKERS LIM- ITED, OF WESTMINSTER, LONDON, ENGLAND, A BRITISH COMPANY.

PRODUCTION AND UTILIZATION OF SMOKE-PRODUCING COMPOSITIONS.

Application filed May 24,

To all whom. it may concern.

Be it known that we, ()wEN DAvm LUoAs and FREDERICK GEOFFREY LENS JonNsoN, both subjects of the King of Great Britain, residing, respectively, at 49 Linden Gardens, Bayswater, in the county of London, England, and Vickers House, Broadway, l/Vestminster, in the county of London, England, have invented certain new and useful Improvements in Production and Utilization of Smoke-Producing Compositions, of which the following is a specification. I

This invention relates to the production and utilization of smoke producing compositions, especially coloured smoke for military and pyrotechnical purposes, and has for its chief object. to increase the rate of evolution of smoke and to control it according to the conditions of smoke emission required.

According to the present usual method of utilizing smoke compositions in shells, bombs, rockets or other missiles and smoke screen producing apparatus, the container is either filled with a single large pellet or the composition is pressed into the container, with the result that the evolution of smoke does not start properly until some time after ignition, and continues at a rate depending on the composition itself.

According to this invention the container is filled with the smoke composition in the form of pellets or tablets of a predetermined size so as to provide a large surface for ignition and production of the sn'ioke, which therefore starts at once in full volume and finishes sharply on the burning out of the composition. The composition employed may be of any type giving any desired colour and the relatively large surface of emission provided gives a very rapid action and prevents any great increase in temperature as the burning of the composition proceeds, so that the smoke is emitted at a fairly constant rate from ignition -to the end of combustion.

The size of the pellets or tablets is determined according to the rate at which the smoke is to be emitted and according to the nature of the composition, the size being readily calculated from the known constants, depending on the rate and temperature of combustion, i. e., the more rapid the combustion of the composition the larger Will be the pellets and vice versa. For ex- 1922. Serial No. 563,314.

ample for typical red, yellow and black compositions of known type the following figures may be given To produce large volumes of smoke in a short time standard red and yellow compositions may be in pellets thick by g" square and the black composition may have a thickness of 3; and a diameter of i.

For the production of smoke at a less rate but lasting for a longer time the pellets may be 1" thick by. g" square for red and yellow and i thick by 5*," diameter for black.

The pellets may be made by mixing the powdered composition with sufficient water,

alcohol or other suitable liquid to produce a dough like mass, which is then moulded in any ordinary moulding apparatus into round, square or other suitably shaped pellets or tablets of regular size. Or the dough produced as above may be' rolled or pressed into a fiat cake or sheet of suitable thickness and cut into squares by cross cuts with a knife or other instrument and laid out to dry.

It has been suggested to use for the production of coloured smoke mixtures containing certain organic colouring matters, a comburent such potassium chlorate and a combustible material such as lactose or shellac, as coloured smoke producing compositions. Lactose containing mixtures possess the disadvantage of losing water when stored for any length of time, and especially in a warm place. with the result that the temperature at which the mixture burns becomes so high that the colouring material instead of being merely volatilized, is decomposed, and moreover the mixture may in time become violently explosive. We have found that the production of coloured smoke or gas from mixtures of the general type comprising a colouring material, a comburent. and a combustible material is dependent not only upon the nature and proportions of the various constituents of the mixture, but also upon the conditions of temperature and pressure under which the combustion takes place. 'In the first place the proportions of the sever il constituents of the smoke-producing mixture or composition should be adjusted so that sufficient heat may be derived from the burning ofthe combustible substance to volatilize the colouring material, while the temperature attained during the burning of the mixture must not be high enough to cause any substantial. decomposition of the colouring material, In the second place the conditions under which the combustion takes place must be so regulated that the pressure developed, while not exceeding certain limits, is sufficient to prevent the coloured cloud remaining too long in contact with the heated slag that results from the combustion, as if this were not the case decomposition of the colouring matter and destruction of the coloured cloud would result.

A smoke-producing unit comprises according to a further feature of this invention a mass of combustible composition stable at normal temperatures and containing volatilizable colouring matter, in a container in which it is adapted to be ignited, the said container having orifices so arrangedthat on ignition the temperature produced is sufiicient to volatilize the colouring matter without substantial decomposition.

The accompanying drawings show two typical smoke charge containers embodying this invention, Fig'm'es l and 2 being respectively a section and an underside plan of the interior of one arrangement adapted to be suspended with its axis vertical and Figures 3 and 4 respectively a section and a face view of a container suspended from the side.

Referring to Figures 1 and 2 A is the outer cylindrical case usually of thin tinned iron, closed at top and bottom by the tinned iron plates or discs a, a of which the latter is formed with a central hole (1 The discs (1. and a are secured in place by turning over the small tongues a. at the ed es of the cylindrical case A. B is a lining of strawboard, asbestos or like heat insulating material enclosing the smoke composition pellets C on all sides, pierced with a central hole b. D is a quickmat'ch passing into the middle of the char e (through a small flanged copper tube a and terminating in a small powder bag F in the center of the char e. The tube E is held in place by the smal disc e of xvlonite or like composition lying under the flangedend of the tube and between the lining B and the bottom plate (1.. G is a wire loop or suspension device attached to the top plate a to enable the con tainer to be suspended from a parachute or other carrier.

On igniting the composition through the quickmatch and powder bag the burning starts in the middle of the mass and the smoke is driven out through the holes 1), a', the quickmatch tube dropping' away. The relation of the smoke emitting hole or holes to the nature of the smoke composition is a matter of great importance as will be shown hereafter.

In the second typical form shown in Figures 3 and 4 and general arrangement is quickmatch in this case passes through both platcsu and a. and-through a small central powder bag F.

The container is suspended by the cord G attached to the cylindrical case A near one edge and a second cord G may be provided for, attachment to any other object. The smoke in this case issues from both sides of the container when the charge is ignited through the quickmatch D and powder bag F.

In order to ascertain what colouring Hiatters are suitable for use in connection with this invention, the powdered colouring matter may be blown through a tube heated to a sufficient and suitable temperature when the formation of the smoke cloud will indicate if it is suitable. For the combustible ingredient of the smoke producing composition a suitable substance is ordinary white su air or flour, especially where a firmly pe leted and coherent substance is required, while for the comburent or oxygen carrier a suitable material is potassium chlorate. We have found that compositions in which white sugar or flour is employed as the combustible do not deteriorate on storage. The proportions ofthe various ingredients of the smoke-producing composition may vary within certain limits. the proportion of colouring material being of the order of fifty per cent, of the combustible twenty or thirty per cent, and of the comburent twenty to thirty per cent. of the total weight of the composition. A detrimental excess of any constituent of the composition may easily be ascertained by its behaviour. Thus an excess of the comburent usually destroys the color and frequently results in inflammation of the mixture, an excess of colouring material causes slow combustion and sometimes completely stops the ignition,

whilst too low pressures or too large orihigher the proportion of sodium-bicarbon- Sugar mwtures.

(1) For yellow smoke:

Auramine -Q a8 parts Sugar 21 parts Potassium chlorate; 31 parts (2) For red smoke:

Oil yellow 52 parts Sugar 27 parts Potassium chlorate 21 parts (3) For purple smoke:

Purple dye No. 80260 50 parts Sugar 20parts Potassium chlorate 30 parts (4) For blue smoke:

Blue dye No. 80073 46 parts Sugar 20 parts Potassium chlorate 34parts Of the above compositions, the yellow has a tendency to inflame under certain conditions, but this may be corrected by the addition of sodium-bicarbonate in accordance with th following example:

(5) Auramine 47 parts Sugar 20parts Potassium chlorate 31 parts Sodium bicarbonate 2parts Flow" compositions. (6) For yellow smoke:

Auraminec 48 parts Flour 24 parts Potassium chlorate 28 parts (7) For red smoke:

Oil yellow 52 parts Flour 25 parts Potassium chlorate 23 parts (8) For purple smoke:

Purple dye No. 80260 50parts Flour 23 parts Potassium chlorate 27 parts (9) For blue smoke:

Blue dye No. 80073 46 parts Floor 2Lpairts Potassium chlorate 30 parts ()f the dyes mentioned in the examples given above, the auramine is that termed auramine 0 Cone made by L. B. Holliday & Co., the oil yellow is British dyes No. 80069, the purple dye is British dyes No.

80260, and the blue dye is British dyes No. 80073.

()f the flour compositions the purple and blue are a little, while the red and yellow are considerably, slower than the corresponding sugar compositions.

it is not essential that the pelleted form of composition be employed in the contain ers. Insome cases the composition maybe presspd into the container under substantial pressure giving a much greater total mass than where loos pellets are used for filling.

The following table gives details of suitable sizes of orifice, weights of compositions employed, and the pressure at which they are compressed into the containers of about 2;: inches diameter and 1% inches depth for various compositions in the unpelleted form:

l Pressure pcr Orificcs (one square inch Colour. at top and m t lior each comone at bot- 0m g position as tom of eon- 0 9051 pressed intainer). to the container.

Inch. Grams l Pounds ed ii 100 50 Yellow i 110 100 Purple i 140 100 Blue 5 140 100 Black l 200 100 For somewhat smaller containers and pel leted compositions the following examples may be given:

Usually the pelleted compositions develop pressure somewhat quicker than the same compositions when merely pressed into the containers, and consequently a larger orifice may be used for the same weight of composition in the former as compared with the latter case.

What we claim and desire to secure by Letters Patent of the United States is i 1. A smoke producing composition comprising colorin matter adapted to volatilize'without su stantial decomposition and intimately mixed self-combustible material made into pellets of predetermined uniform size, whereby the area of the initial ignition surface of the complete charge is controlled.

2. A smoke producing composition comprising coloring matter adapted to volatildiicing unit of the type described, which consists in forming paste of colorlng matter adapted to volatilize without substantial de-V composition and a self-combustible material, and dividing the paste into pellets of predetermined uniform size. whereby the area of the ignition surface of the complete charge is controlled.

4. A smoke producingumt consisting of a mass of combustible composition stable at normal temperatures and comprising a large proportion of volatilizable colouring matter, a comburent and a combustible 1ngred1 ent, means by which the composition can be ignited and a container for the said composition closed on all sides, but prov ded with smoke emitting orifices so roportioned and arranged that on ignition the temperature produced is suflicient to volatilize the colouring matter but too low is produce substantial w decomposition of the said colouring matter.

5. A smoke producing unit comprising a number of pellets or tablets of predetermined uniform size, said pellets consisting of smoke producing composition comprising organic coloring matter adapted to volatilizewithout substantial decomposition, a

comburent, a combustible ingredlent and a smaller portion of sodium bicarbonate mixed with the combustible material to control combustion. i

6. A smoke producing unit consisting of a mass of combustible composition stable at normal temperatures and comprising a large proportion of volatilizable colouringmatter, a comburent and a combustible ingredient, means by which the com )osition can be ignited and a container for the said composition comprising a thin metal case closed on all sides and provided with a heat insu-' lating lining and having an aperture for admission of the ignitions means and smoke emitting orifices so proportioned and arranged that on ignition the temperature produced is suflicient to volatilize the colouring matter but too low to produce substantial decomposition of the said colouring matter. a

7. A smoke producing unit consistin of {a mass of combustible material in the form the pellets are packed, said container having smoke emitting orifices so proportioned and arranged that on ignition the temperature produced is sufiicient to volatilize the colourin matter but too low to produce substantial decomposition of the said colouring matter.

OWEN DAVID LUCAS. FREDERICK GEOFFREY LEES JOHNSON.

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