US2299466A - Power generating unit and igniting means therefor - Google Patents

Description

Oct. 20,1942. R. A. cor-FMAN POWER GENERATING UNIT AND IGNITING MEANS THEREFOR Filed April 23, 1936 2 Sheets-Sheet 1 2 Sheets-Sheet 2 R. A. COF FMAN Filed April 23, 1936 POWER GENERATING UNIT AND IGNITING MEANS THEREFOR Oct. 20, 1942.

Patented Oct. 20, 19442 UNITED STATESA PATENT oFFlcE POWER GENERATING UNIT AND IGNITING LIEANS THEBEFOB Roscoe A. Caiman, Hollywood,

Y Application lim-n z3. 193s, serial' No. 76,059

In Germany February 8, 1935 21 claims. (0.1.102-12) This invention relates to pressure creating units and method of applying the same. A device of this general character is illustrated in my U. S. Patent No. 2,005,913, issued June 25,

- 1935, upon an application filed May 11, 1931, and

also in my pending application, Serial No. 581,032, filed December 14, 1931, where there is disclosed a cartridge for generating pressure to be utilized in an expansion motor for internal combustion engine starters. While the cartridge of the present invention is of utility in the same relation, I wish to make it clear at the outset that it is by no means limited to that particular field,

accomplished by the proper blending of fuels,

fore the pressure will not snu out the flames of the slow-burning (nitro-cellulose) fuel. This is such as nitroglycerine bearing fuels in the various percentages with nitro-cellulose or other nonbut that it has a wide range of applicability, and

that it is intended to be used in any relation where a self-contained pressure generating unit may loe employed to advantage. Therefore, merely as a means of bringing out certain char- A acteristics of the device, I have illustrated in the accompanying drawings a part of the system disclosed in my patent aforesaid, .but irais to be understood that this is not to be construed as limiting with respect to the uses to which the invention may be put, nor necessarily as a part of the invention.

The major object of this' invention is to provide a small portable unit assembly, capable of generating within a closed system, a suicient volume of gases, and superheating the same to a maximuml of expansion to pressures sufdciently low to he accurately controlled, hut great enough to, within a limited space, develop a preponderance of horse power sumciently great to perform a given amount of useful work when used in connection with a device adapted to receive the same. y

Another object of the invention is to provid in such unit assembly a fuel capable of generating gases and superheating same at a predetermined rate sufficiently rapid to perform the determined work operation, yet sufficiently slow to avoid injurious shock to the device or mechanisms to which the resulting power is transmitted.

A further object of the invention' is to provide a fuel suiiiciently slow burning as to be capable when ignited, of propelling a major portion of the fuel contained in the unit toa point remote from the initial point of the ignition and there burned to maintain the necessary pressure.

Another object is to provide in such unit a non-detonating igniting means producing a fiame of sufficient duration and heat to insure the ignition and combustion of the fuel within said unit,

nitro-glycerine bearing fuels as fully set forth herein.

A still further object of the invention resides in the construction of the unit charge whereby provision is made for igniting the fuel at or near theforward end of said unit and thus permitting the fuel within the shell or cartridge to be withdrawn therefrom in acomparatively steady stream into the system as the burning of the fuel progresses. This is accomplished in part by the provision of an ignitingV tubeextending throughY the fuel for creating a train of fire through the unit, and is particularly useful in the longer types of these power generating units.

A further object of the invention is to provide a power generating unit of the character disclosed wherein a hot flash match is used, and where an igniting tube is associated therewith extending from said match through the fuel charge within the unit and in a direction longitudinally of the unit, said tube not only serving to ignite the fuel throughout its length, but also acting as a conveying means, through the body of fuel, for the ame from the hot flash match, and for the purposes intended.

Another object of the invention resides in the construction of such a power generating unit wherein provision is made for conveying a continuous hot flash flame from the primary igniting means or base of the unit to the forward end of said unit, whereby the completely consumable closure element or wad at said forward end, is instantly burned to openup the Aunit and permit the fuel to be properly released from said unit for subsequent delivery to the remote point of use in the system being operated.

Another object of the invention is to provide in a power generating unit of the character disclosed, a dual igniting device made up as a unitary structure, and for ignition of the fuel within said power generating unit, whereby said fuel may be ignited or fired by either a percussion cap,

or by electrical igniting means, such as an electric match; the unitary igniting device being soconstructed and arranged as to insure ignition of the match heat composition when firing the unit charge by means of percussion.

This and other objects and advantages of this invention will become apparent in the following description, in which the appearance of like reference numerals indicate like parts, and in which:

Figure 1 is a view of a portion of the system assembly disclosed inA my aforesaid patent illustrating the cartridge receiving breech'block, expansion chamber and cylinder, and the connecting conduit therebetween; t Figure 2 is an enlarged fragmentary sectional view of a form of pressure charge generating unit constructed in accordance with the invention and illustrating particularly a pressure creating unit capable of being ignited either by an electric match or by means of a percussion cap, the same constituting a single unitary device for ignition purposes;

Figure 3 is a detail view in perspective showing the sleeve extension with the V-groove for receiving the bridge wire, as used in the form of the invention illustrated in Figure 2;

Figure 4 is a vertical section of a shell constituting another form of pressure charge gen` erating unit constructed in accordance with this invention and illustrating in particular the tetryl di-chromate lined cellulose tube for use in combination with a match head igniting means;

Figure 5 is a vertical section of a still further form of pressure 'charge generating unit, illustrating a tubular type of solid pellet with a layer of tetryl di-chromate mixture adhering to the interior bore of said pellet;

Figure 6 is a view in section illustrating a still further modification of the pressure charge generating unit, showing a different form of cellulose igniting tube;

Figure '7 is a fragmentary sectional"'view of a further modification of the pressure generating unit, showing the cellulose igniting tube in association with a percussion cap instead of a match head igniter; and

Figure 8 is avertical section of a form of pressure charge generating unit constructed in accordance with the disclosure of Figure 2, and showing the tetryl di-chromate lined cellulose tube surrounding the dual-igniting device.

In the particular embodiment of the invention illustrated in Figure 4, A designates a shell comprising a tubular member 5 of cartridge paper or any other suitable material and a oferrule, 6 crimped thereon in any well known way.

This ferrule is provided with a central opening 1 adapted to receive a circuit completing pin 8.

2,299,486 v fk- Figurer said remue is thus included in a circuit dlametrically illustrated at B in Figure 4 and the match head I6 will be ignited when the pin 8 is thrust inwardly to contact with strip Il,

the circuit being then completed from the source of E. M. F. indicated at C, from pin 8 through strip Il, match head I6 and ferrule 6 back to the grounded side of the circuit, or in other words. to the breech block.

The circuit preferably includes a switch, indicatedat D, so that after the shell has been placed in the breech block, the pin 8 may be moved into contact with strip I4 and left. in contact with the switch D open. This provides means for distance control of the shell, it being apparent that the match head will be ignited under these conditions, when the switch is closed, either manually or automatically.

The body 5 of the shell contains a burnable, nonexplosive pressure generating fuel E and it is in the characteristics of this fuel that part of the novelty of the present invention resides. One form of fuel which I have found to be highly eiiicient in accomplishing the objects sought, consist of grains of nitro-glycerine fuel mixed with nitro-cellulose fuel of such size and/or construction and/or relative proportions ofsizes as to produce a fuel which, when ignited by the match head, will burn rapidly and generate a very con'- siderable volume of usable propulsive gases without detonation, shock, or jar. I find that by suitably proportioning the sizes of the grains used or by varying the construction of said grains (as for example by piercing them with a greater or less number of small holes) I can control the rate of 4burning very accurately, and underv the present invention I do so control the rate of burning as to discharge from the shell a large quantity of heated gases together with such quantity of the fuel as to carry on combustion and maintain and/or progressively increase the heat volume and pressure of the gases over a desired length of time but without explosion, shock,- or jar, and Without detonation.

Furthermore, I vary the rate of combustion of some of the grains with respect to the rate of combustion of other of` the grains, so that the gas from the rst burning grains may serve to quickly build up a desired pressure and heat surfaces in contact vwith which the gases are to come, and the slower burning grains will thereafter maintain the heat of these gases and cause their continued expansion for the performance of the desired work.

'A furtherimportant point of noveltyinherent in the present invention is that under certain desired conditions I so arrange the rate of burn- Discs 9 and IIJ of insulating material are lo- 60 cated inthe bottom of the shell, and the disc 9 is provided with a safety aperture'lfl which aligns with the central opening of the ferrule. A sleeve of insulating material, indicated at I2, is received within these openings and serves to prevent accidental contact of the pin 8 with the metal of the ferrule. A contact strip I4 is disposed between the discs 9 and l0, and a iine bridge wire leads therefrom through a match head composition I6, the bridge wire being continued in the form of a metallic strip I1 back to the ferrule, and said strip being bent into engagement with said ferrule as at I8. It is clear, therefore, that if a shell of this character is placed ina grounded breech block, such as that indicated at I9, in

ing of the fuel within the shell 5 that the portion of the fuel first ignited generates suicient gas before the ignition of the last of the fuel, that any desired part of the fuel is propelled, before being ignited or before being burned, from the shell, and to another point where useful work is to be done and there ignited and/or burned. A shell having the latter characteristics is of ture of Figure 1 where 20- designates atcombustion chamber to which the gases discharge from the shell, along with the unconsumed fuel are conducted through a tube, 'or'conduit 2|, from the discharge nozzle 22 of the breech block.

It will be observed that the tube or conduit 2l constitutes a pathof some considerable length and Consequently this tube SeXVeS 81S 8.' leSel'VOI' within which a considerable volume of gas isA generated prior to the time that a piston 23 within the cylinder 24 and upon which the gases are designed Vto act, begins to move, so that after the largely determines the amount of fuel which'willV be consumed within the shell, and the amount which will be propelled from the shell to another point to be consumed at the latter point. That is to say, by locating the match head I6 nearer the iront of shell (and this may be accomplished by merelyV extending the Wires leading to said match lead) more of the fuel will be consumed within the shell and discharged therefrom as gas and less will be propelled from the shell in unburnedform. Such. a construction is shown, for instance, at Figure 52 of my Patent No. 2,005,913 of June 25, 1935, where the match head 83 is directly beneath and in close prommity to the combustible wad over the end of the shell. From experience and tests, however, this construction has been found to be impracticable for comercial use, and this due to the melting of the solder on the match head or to the burning through of the lead wires which for the entire length of the shell are subjected to the intense shown in said Figure 52 of my patent just mentioned. Due to these last mentioned conditions, pieces of metal in the match head frame are loosened and become detached and are invariably carried into the system and the starter operating mechanism, thereby causing considerable troubler' The ignition means hereinbefore mentioned heat of the charge i85 contained within the shell 4,

cuprous-acetylide or .other non-corrosive substance ignitable at approximately 450 F. which insures a suilicient name to ignite a coating thereto composed'of any non-deleterious composition which will burn with a hot ash of pro- T longed duration. This coating is obtained by again dipping the frame of the match head into a mixture of approximately 75% tetryl and approximately 25% of potassium xii-chromate or lol-chromate or chromate mixed in powdered form with a suitable binder, such as, for example, collodion liquid nitro-cellulose or any other binding material which `will cohesively bind'the whole together as an operative match head. It is important that the 'compositions forming this match head are such that they will neither of their own account nor by admixture with the formulated gases of the other fuels in the shell form a deleterious gas which will deteriorate the metal or other component parts of the device with which the shell is used.

The type of fuel in the shell is such that if in a. cartridge of given diameter, the' body of the fuel is sufiiciently deep or long, the individual grains of fuel may bind themselves on the side of the shell casing and in such eventuality aconsiderable amount of undesirable pressure will be generated at the back of the fuel (base of the cartridge), before the fuel: will start moving out of the shell. Such a condition obviously exerts a tendency to break up the fuel and creates an undesirable pressure condition sumcient to blow the fuel out of the shell in a wad formation instead of a steady stream desirable for smooth operation in the system.l I have found in actual practice that a longer sized or deeper shell is necessary under cold or extreme cold weather conditions and I have further provided, for use in combination with this match head a completely disintegrating and consumable tube i9' composed of nitro-cellulose film or other similar or suitable substance, internally coated with a mixture of tetryl di-chromate or tetryl bi-chromate in the respective proportions of approximately 75% tetryl and, 2\5% di-chromate. This tetryl di-chromatem lined cellulose tube is operatively placed over the match head at the base of the shell a'extends to the consumable wad 20 which Vforms the closure. I am thus enabled to elongate the steady hot flame from the rear of the shell to the front of the shell and thereby insure initial ignition of the shell pellets disposed at the front or the forward end of the shell. Also, by the use of this tube I am enabled, immediately upon initiating ignition of the unit charge, to conduct the hot flash name through burns theicompletelyzbhsurable closure element or wad and permits the immediate and proper release of the ignited fuel charge from the shell for subsequent delivery to the place of burning for creating gases to perform a useful work operation. I prefer in the longer type of shell to place the majority of the nitro-glycerine bearing fuel in the front end of the shell so as to further insure ignition of the fuel in the front portion of the shell and thereby support the ignition of the nitro-cellulose fuel from the front as well as from the rear as in the shorter type of shell. This tube" may be made of spiral Wound nitrocellulose nlm, or it may be a nitro-cellulose tube formed by extrusion; furthermore, it may be formed of double base material of the same composition as that ofdouble base nitro-glycerine bearing nitro-cellulose powder -or fuel; and/or this tube may be lined with a mixture of tetryl cli-chromate or tetryl chromate mixture and mixed with a suitable binder such as a, liquid nitro-cellulose or other combustible consumable binder. Furthermore, said tube may be lined or coated on the inside, .or it may be lined or coated on the inside, and/or coated Von the outside. Still further, said tube may be lined with a suitable mixture of zirconium and a suitable oxidizer such as barium nitrate or chromate or di-chromate, and the tube treated withthis mixture the same as described forvtetryl and di-chromate. By the use of zirconium and a suitable oxidizer, to-

gether with a suitable binder, it is possible to i6. but also the flame from the tube and tube liner of tetryl dichromate, proceed at once to the fort ward end of the shell to immediately burn a hole through the consumable wad 20. :At the same time, the burning' of the tube i9' Vcreates a train of iire Afor practically the entire length of the shell and ignites the fuel in contact therewith or in close proximity to said tube I9.

Also in the use of this tube it is desirable to place the double base or nitro-glycerine bearing, easily ignitible, booster or kindling. fuel, in the forward end of the shell (instead of at Jthe rear around the match head I6) so that by igniting this fuel in the forward end of said shell, the remainder of the fuel charge at the rearYA will be withdrawn from the shell by suctioninto the system as the burning of the fuel progresses.- From actual experiments and experience, this action has been found to take place. f Y

The tube may also be placed in a shell of the character described, with the lower end of the tube surrounding a percussion type of initiator (instead of a match head), such for instance, as shown at 2| in Figure 7 of the drawings, the tube in this figure being designated at |98.

In the solid pellet type of fuel, such as shown in Figure 5, the lining 22 of the solid pellet 23 may be of tetryl di-chromate or zirconium and an oxidizer as heretofore described in connection with the tube I9. This lining may also be in the form of a coating, or it may be a thin film or layer of double base or nitro-glycerine bearing nitro-cellulose fuel, and furthermore, may be made as an integral part of the solid pellet 23 by the extrusion method.- The solid pellet 23 may be made of straight nitro-cellulose fuel, and on the outer end of said pellet, as shown in Figure 5, there may be provided a cap or wafer 24 made of nitroglycerine bearing double base fuel, which is easily ignitable, and which would serve to insure the ignition of the front or forward end of the solid pellet 23, after the action of the tube 22 has taken place as heretofore described Yfor igniting purposes. This wafer 24 has a hole therethrough of the same size as the bore of the solid pellet 23 and as a matter of fact said hole forms 'an extension of the bore. It is also well to note in this connection that the lining or coating just referred to extends over the interior surface of said pellet and up to and through the hole formed in the wafer. The match head used in connection with this'type of power generating unit is shown at the bottom -of the solid pellet, and indicated at 25 in Figprolonged and elongated-hot flame in an ordinary weather type of shell. In addition thereto, I have provided completely consumable tube means for securing the necessary prolonged hot flame to properly insure ignition without a prior building up of pressure in the longer and deeper cold or extreme cold weather type of shell. The means here provided enables me to ignite and burn fuels which are, as is well known, normally susceptible to the phenomena of expiosive chemical reaction without approaching an explosive chemical reaction or disturbing the explosive chemical equilibrium of the fuel.

It is well to note that I have found by experience that the ordinary type of match head is undesirable and useless for the purpose of this invention in that the ordinary match head usually contains chlorates. ignites with a snap which is highly akin to detonatic-n, does not produce a prolonged and elongated hot ame as is necessarily secured by the match head described herein, and in actual practice the ordinary and known match head results in breakage of the associated unitary structure.

mechanism with which I prefer to use my shell.

In the form-of the invention illustrated in Figure 2 of the drawings, I have provided a. new type of initiator or igniting means for the power generating charge 25a within the shell 26, this initiator capable of being fired either electrically or by percussion, and the same being made as a single In this Figure 2, a conventional percussion type of initiator is shown at 21, with the outer shell of the priming cap indicated at 28, and the center of the point where the strikcussion Abeing indicated at 29. Also at 30 is shownv a. pin which serves not only as the ring pin for the percussion type of firing, but also as the hand operated electrode for the electric type of firing. A brass or other metal sleeve 3| surrounds the percussion cap 21 and is insulated therefrom by means of an insulator 32 of fiber, paper or some other suitable insulating material, the` parts being rigidly held together as a unitary structure, which device may be pressed through a central opening in the metal ferrule 33 of one of my conventional cartridge type power generating units. The sleeve 3| and the ferrule 33 of .the cartridge shell are in closeelectrical contact, and extending from the sleeve is an extension 34 having a V-groove 35 for receiving one end of a bridge wire 36, the other side of said bridge wire being received within a V-groove 31 formed within an extension 38 of the priming cap 21.v After the bridge wire is inserted within the V-grooves of the extensions 34 and 38, the two legs of each V` grooved extension are pinched together to hold the bridge wire 36 firmly in place, and thus make electrical connection -between the sleeve 3| and the priming cap 21. This bridge wire may also be soldered to the extensions 34 and 38 as indicated at 39 in Figure 3, after which said bridge wire and the extensions 34 and 38 are dipped in a composition of cuprous acetylide, then dried, and afterwards dipped in a composition of tetyrl dichromate or other suitable hot flash composition, thus forming a match head of the character herein referred to, the cuprous acetylide coating being indicated at 40 and tetyrl di-chromate coating indicated at 4|. In this connection it is Well to note that the cuprous acetylide ignites at a low temperature and in its burning operation produces a sufficient heat and flame to ignite the outer match head coating 4| of tetryl di-chromate or other suitable hot flash composition which burns with a hot flame instead of an explosion.

I'he combustible substance in the priming cap chamber is composed of any one of several well Lknown percussion types of materials,which,when

fired expel a long hot flame through the orifice structure a device having dual ignition means,-

Whereby the power generating unit may either be red electrically (as for instance, by an electric match) or else by means of the percussion type of ignition.

In the event it isdesired to use the electrical through the percussion cap frame 21, the extension 38, bridge wire 36, the extension 34, sleeve 3l, and thence to the metal ferrule 33 ofthe shell back to the grounded side of the circuit, or in other words, to the breech block. y

If for any reason the electrical ignition does not function, firing pin 30 may be suitably-drawn back and snapped in a well known way,and by percussion re the percussion powders in the primer cap 21, projecting a flame through the orifice 42 which will ignite the match head and also the kindling and other fuel located within the shell and within range of said ame.

An asbestos wad 43 is placed in the bottom of the shell to act as a cushion or seal around the metal sleeve 3l, and to prevent the shell from leaking around the priming device.

It is also an embodiment of this invention to place a tube of the character described and of suitable length within a shell, and with the lower end of said tube surrounding a. match head type of initiator, and with the upper end of the tube cemented or otherwise secured to theside of the cartridge shell. Such a tube is shown for instance at I9b in Figure 6 of the drawings, and the point of cementing the tube to the side of the shell is indicated at M, in said gure.

It is also well to note that in Figure 8 of the drawings, a tube of the character described herein is illustrated at i9", and that thisA tube surrounds a dual igniting means of the type illustrated in Figure 2 of the drawings, the dual igniting means being indicated generally at 45 and the tube extending therefrom and through the fuel within the shell in a direction longitudinally of said shell, and for the purposes heretofore set forth. ,l

In the drawings the nitro-glycerine bearing fuel pellets (easily ignitible and hard to extinguish) are shown as shaded pellets, thus indicating their preferable location with respect to the 3. In a power generating unit of the character described', a shell containing a charge of deflagrating burnable fuel in such quantity to deliver, when ignited and burned, a suiciently large volume of gas to perform an appreciable amount of usefulwork and wherein said fuel is composed Iof a multiplicity of pellets some of which are faster burning than others and adapted to aid in maintaining ignition and support combustion-bf the slower burning pellets, a hot ash means at' the base of said shell, and a nitro-cellulose tube lined with tetryl di-chromate associated with said hot flash means and extending longitudinally through the charge of fuel for insuring proper ignition of the faster burning pellets withinisaid shell. Y

4. In a power generating unit of the character described. a shell containing a charge of deflavgrating burnable fuel in such quantity to deliver,

when ignited and burned, a sufficiently large volume of gases to perform an appreciable amount of useful work and wherein said fuel is composed Aigniting means and extending 4longitudinally 'of a multiplicity of pellets some of which are through the charge of fuel for insuring, when burning, the ignition of the vfuel within said V shell.

5. In a power generating unit ofthe character described, a shell containing a charge ofdeflaof the power generating units herein described,

said nitro-cellulose fuel Vpellets being unshaded.

What I claim and desire to secure by Letters Patent is:

1. In a power generating unit of the character described, a shell, a body of dilcultly ignitible deflagrating main fuel of a material of such nature that its rate of burning increases with increase of pressure. a deagratng kindling fuel associated with said main fuel, a primary igniting means at the base of said shell, and a nitro-cellulose tube lined with tetryl (ii-chromate associated with said igniting meansand extending through the body of main fuel forl insuring proper ignition of the fuel charge at the forward end of said shell.

2. In a power generating unit of the character described, a shell, containing a charge of deflagrating burnable fuel in such quantity to deliver, when ignited and burned, a suciently large volume of gas to perform an appreciable amount of useful work and wherein said fuel is composed of a multiplicity of pellets some of which are faster burning than others and adapted to aid in maintaining ignition and support combustion of the slower burning pellets, a primary igniting means at the base of said shell, and a nitro`cellulose tube lined with tetryl di-chromate associated with said igniting means and extending through the charge of fuel for insuring proper ignition of the faster burning pellets within said shell.

grating burnable fuel in such quantity to deliver, when ignited and burned, a sufciently large volume of gas to perform an appreciable amount of useful work and wherein said fuel is composed `cf a multiplicity of pellets some of which are faster burning than others'and adapted to aid in maintaining ignition and support combustion of the slower burning pellets, said faster burning pellets being located at the forward end of said shell, a primary igniting means, and a kindling means ignited by the igniting means and extending Vthrough said charge of fuel to insure, when burning, the ignition of the faster burning pellets within said shell. Y

6. In a power generating unit of the character described, a projectile free shell containing a body of deagrating main fuel, a kindlin'g fuel associated with said main fuel, a primary igniting means at the base of said shell, and a burnable fuel tube of material capable of being completely consumed -without ash or other objectionable vful work, akindling fuel associated with said main fuel at the forward end of the shell,` a primary igniting means at the base of said shell, and a burnable fuel tube of material capable of being completely consumed without ash or other objectionable residue ignited by said igniting means and extending through the body of main ,fuel to a point adjacent the kindling fuel to insure ignition thereof, said tube beingf unobstructed to permit the ash from the primary igniting-means to be properly projected therethrough. :f

8. In a power generating unit ofthe character described, a projectile free shell containing a charge of deagrating burnable main fuel in such an orifice through which is projected a hot ash quantity to deliver, when ignited and burned, a

-when ignited, to the forward end of said shell,

and a kindling fuel associated with said main fuel and located adjacent the forward end of said tube.

9. In a power generating unit of the character described, a shell containing a charge of deflagrating burnable fuelin such quantity to deliver, when ignited and burned, a sufficiently large volume'of lgas to perform an appreciable amount of useful Work, a primary igniting meansat the base of said shell, and a nitro-cellulose tube lined with tetryl di-chromate associated with said igniting means for use as a conveying means for a hot flash name from said primary ignitingl means to the forward end of the shell and also serving to insure proper ignition of the fuel charge within said shell.

10. In a power generating unit of the character described, a projectile free shell containing a charge of deflagrating burnable fuel in such quantity to deliver, when ignited and burned, a suciently large volume of gas to perform an appreciable amount of useful work, an igniting means at the'base of the shell, and a tube of material capable of being completely consumed without ash or other objectionable residue when burned and surrounding and extending from said igniting means throughthe body of fuel with the outer end of said tube closely adjacent and anchored to the side of the shell at a point short of the forward end of said shell.

11. A power generating unit of the character described, a shell, a solid body of difilcultly ignitible main fuel within said shell and having a bore therethrough arranged longitudinally of said shell, a lm or coating of tetryl di-chromate upon the interior bore of said fuel, an igniting means at the base of said shell extending into the bore vat the lower end of said body of fuel, and a wafer of nitro-glycerine bearing double base fuel at the .forward end of said shell and associated with said solid body of fuel, the tetryl di-chromate lining or coating also extending through the wafer.

12. A power generating unit of the characterfiame for igniting said fuel when the percussion cap is fired, and a match head located within the shell for producing a second and independent hot flash flame within the shell when ignited for igniting the fuel, said match head being so associated with the percussion cap as to be ignited by the hot flash flame projected through the orifice of said percussion cap.

14. A power generating unit of the character described, a shell containing a body of deilagrating fuel in such quantity as to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful work, a percussion cap associated with the base of said shell having an orifice formed therein through which a hot flash flame may be. projected within the shell to ignite said fuel, and an electric match mounted on said percussion -cap` and insulated therefrom so as to be firedelectrlcally, the head of said electric match being so positioned with Arespect to the percussion cap orifice as to be ignited by the hot flash flame projected through said orifice and simultaneously with the ignition of said fuel for projecting a second hot flash flame within the shell for ignition purposes. V

15. In a power generating unit of the character described, a shellHcontaining-jacharge of deflag-ratingburnabl' fuel in'such'quantity to deliver, when ignited and burned, a sufficiently large volume of gas to perform an appreciable amount of useful work, a primary igniting means at the base of said shell, and means having a tetryl di-chromate coating associated with said igniting means for use as a conveyor for a hot ash flame from said primary igniting means to the forward end of the shell and also serving to insure proper ignition of the fuel charge within said shell.

16. In a power generating unit of the character described, a projectile free shell containing a body of deagrating fuel in such quantity as 'to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful work, an inflammable closure for said shell, an igniting means for said fuel, and an unobstructed burnable and completely consumable tube within the shell and extending through the fuel for conveying the flame from said igniting means toward the closure end of said shell for also igniting the closure, saidI tube when burned leaving no ash or other objectionable residue in the gas being generated.I e

ing fuel in such quantity as to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful work, a percussion cap associated with the base of said shell having 17. In a power generating unit of the character described, a projectile free shell containing a body of deilagrating fuel in such quantity as to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful work, aninilammable closure for said shell, an igniting means at the base of the shell-for igniting the fuel, and burnable and completely consumable means unhampered by the fuel for causing the flame of said igniting means to simultaneously ignite the closure, said completely consumable means when burned leaving no ash or other objectionable residue in the gase being generated.

18. In a power generating unit of the character described, a. projectile free shell containing a body of deagrating fuel in such quantity as to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful work, an inflammable closure for said shell, an igniting means for said fuel, and an unobstructed-burnable and completely consumable tube within said shell and' extending through the fuel for conveying the ,flame from said igniting means toward the closure end of said shell for also igniting the closure, said tube coated with a substance to promote and sustain said flame along the tube, and said tube and its coating being of such character when burned as to leave no ash or other objectionable residue in the gas being generated.

19. lna power generating unit of the character described, a projectile free shell containing a body of deiagrating fuel in such quantity as to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful work, an inflammable closure for said fuel, an igniting means for said fuel, and an unobstructed burnable and completely consumable tube extending longitudinally through the fuel for conveying the flame from said igniting means toward the forward end of said shell for lsimultaneously igniting said closure, said ntube being of such character when burned as to leave no ash or other objectionable residue in the gas being generated.

20. In a power generating unit of the character described, a projectile free shell containing a body oi deagrating fuel in such quantity as to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful work, an inammable closure for said fuel, an igniting means forsaid fuel, and an unobstructed burnable and completely consumable tube extending longitudinally through the fuel for conveying the ame from said igniting means toward the forward end of said shell for simultaneously igniting said closure, said burnable tube coated with a substance to promote and sustain said ilame along the tube.

2L. In a. power generating unit of the character described, a projectile free shell containing a body of deflagrating fuel in such quantity as to deliver, when ignited and burned, a volume of gas to perform an appreciable amount of useful Work, an igniting means for said fuel, and burnable and completely consumable means extending longitudinally within the shell for conveying the flame /from said igniting means toward the outer end of said shell, said burnable means coated with a substance to promote and sustain the flame to properly ignite the fuel within the shell.

ROSCOE A. COFFMAN.

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