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Патент USA US2403907

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July 16, 1946.
L. A. BuRRows ET AL
2,403,907 ’
SMOKE PO'I..I IGNITER
Filed Aug. 12, 1942
7
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Ajwmldia
INVENToRs '
Patented July 16, 1946
2,403,907
UNITED STATES PATENTz OFFICE
2,403,907?
SMOKE. POT IGNI'IIER.
Lawton A. Burrows, Woodbury, and George A.
Noddin, Wenonah, N. J., assignors to E., I'., du
Pont de; Nemours & Company, Wilmington,
Del., a corporation of Delaware
Application August 12, 1942, Serial No. 454,562
3; Claims. (Cl. wilg-704.2.)
1
Z.
This invention relates to a novel ignition as
sembly, and particularly one adapted for use
where the ready ignition, ofl fuel oils or other
combustible materials» is desired by remote con
particularly on the sides removed from the in
itiator- cavity. By this means the name from
trol, without the necessity of personalv super
vision of each device.
Occasions arise frequently Where the. con
trolled firing or lighting of' units of combustible
materials is tedious and where individual atten
tion to each of such units would :be too time
consuming or would require an excessive amountl
of labor. Orchard heaters, for example, are used
for the protection of fruit trees against frost, and
delay in the lighting of a large number of such
heaters may be serious because of the wastey of
fuel in the case of those ñrst: lighted, or- undue
exposure to cold in the case of trees last pro
the deflagrating: charge, upon initiation, will be
directed out on the side adjacent to the initiator
. cavity toward? the material to be ignited. Pref
erabl'yÍ the main deflagrating charge will com
prise black powder in block or pellet form, and>
we desirably enclose this in a Wrapping of a
flexible metal.
The apparatus: of our invention may be under
stood more clearly byy reference to the accom
panyingV drawing; in which one embodiment is
shownfby way- of illustration. Figure l is an
elevation of" a black powder pellet adapted to
.serve as> the main deñagrating charge. Figure
2 is a cross-sectional View of an electric squib,
suitable for use in initiating the combustion.
Figure. 3‘ isî a vertical elevation cut-away of the
tected. Similar problems' may be met. in the
ignition assembly according,Y to the invention.
lighting of Warning lights; in road construction
or repair work, in the ignition of smoke pots for 20 Referring in more detail to`r the drawing, l in
Fig. 1 showsV a. substantially cylindrical black
obscuring purposes, in the instantaneous light
powder pellet having Within it a cavity 2. A
ing of a large number of signals, and in other
convenient size for such pellet is a length of
fields.
2 inches and a diameter- of approximately 11/¿1
Electric ignition would be a desirable solution
to the above problem, but diliiculties. are metl
In Fig. 2, an electric squib or igniter is shown
when it` is desiredA to ignite, electrically a. large
of a4 type suitable for use in bringing about the
number of bodies of diflicnltly-ignitible heavy
deflagration of' the black-'powder pellet. The
oil for example. It
necessary that. ignition
metal shell' 3, for example of a copper alloy,
be assured, regardless of weatlfierI conditions,
ïhavingr a. length of 1% inches and a diameter
wind, precipitation, andl the like. commercially
of about. 1A. inch, containsv av 5-grain base` charge
available electric squibs are not suitable: because
4 of` a. mixture adapted tov give a very high tem
of the short duration of the flame, and it. is es
perature onr ignition, for example 87.5' parts of
sential; that a considerable source of; heat- be
barium peroxidev and 12.5l parts of ñnely divided
appliedv for an appreciable time interval.: at the
spot, Where ignition is to take place. No prac 35: magnesium. On this base charge is a super
posed ignition charge of 10 grains of a- blend of
tical assembly or device is: now available for ac
83.3 parts of barium peroxide, 14.7 parts of
complishing the foregoing purposes.
selenium, and 21 parts of' powdered aluminum.
An object of the present invention is an. ig
The.V leg or leading Wiresl ‘l from the electric
nition assembly- suitable; for use Where diilicultly
ignitible materials are present. A further object 4(1): ‘ig-niterf aret held iirmly in a predetermined posi
tion by passage through a plug 8k of tightly lit
is such an assembly adapted to bring about the
tingv material; such as a sulfur composition or>
substantially simultaneous; ignition or a. number
rubber, the ends of the wires being connected
of bodies of such materials without the necessity
by` a smaller diameter wire of high resistance 9. ‘
of attention to the individual. operation. AA still
further object is such an assembly- su-ñiciently 45'. This fine Wire is surrounded by a Ibead of' com
bustiblefmaterial> Gf adapted to yield a hot llame `
protected from the influence of weather and
on ignition; The firing of this bead is brought
Water to assurel its proper functioning. Addi
about by> the passage of an electric vcurrenttional objects will be disclosed, as the invention
through the Wires 1f, which causes the heating
is described more at length hereinafter.
of the bridge wire: 9i to incandescence and' the
We have foundl that the foregoing objects
consequent inflammation of the. bead material.
are attained when We employ an» ignition as
This, in turn, initiates the charge 5 and brings _
sembly comprising a main charge of a deflagrat
about the ignition of the base charge 4.
ing explosive having a. cavity therein,l an` elec
Fig. 3 shows an assembly of elements that act
tric initiator within this cavity, and confining
means about the charge of deñagrating explosive,~ 65 in. conjunction with one another» to; produce the.
inches.
y
y
2,403,907
3
4
desired results. The black powder pellet I has
but it is essential that the squib charge employed
a cavi-ty 2 into which the electric squib 3 is in
serted. The leg wires 'I are shown emerging from
be suñîcient to bring about the sure ignition of
the main charge. We find it desirable to use
the squib and pass up on opposite sides of the
in the sc_luib` a composition including an oxidizing
agent and a finely divided metal characterized
by having a, high heat of combustion. The use
pellet, being joined above in a twisted relation
ship. These wires serve to support the pellet and
of blends of barium peroxide and finely divided
magnesium metal answers this requirement sat
isfactorily. The exact type of igniter or the com
powder pellet is tightly enclosed within a sub
stantially cylindrical container of a flexible metal 10 positions included are not essentials of the in
vention. While we have shown a type in which
I0, for example a lead alloy containing a low
initiation is effected by means of an inflammable
percentage of antimony. This container tube
bead, the concave plug type of initiator may be
may be made by any desired method, such as ex
used equally well, that is to say one in which
trusion, and the method of preparation is no part
the plug has a concave cavity at its lower end
of the invention. This flexible metal tube com
in which an ignition composition is enclosed and
prises at its bottom a circular piece of a similar
brought to ignition by the bridge wire.
metal, for purposes of support, having a water
Our preferred form of assembly encloses the
tight well 2 of like metal extending upward in
main explosive charge in a cylindrical sheath of
the center into the cavity in the pellet. This
well serves to contain the electric igniter. The 20 metal. This is desirable because of the Water
prooñng effect imparted.. The metal tube is not
entire metal cylinder is desirably closed at the
top by having the edges folded over and crimped,
essential, however, and the black powder pellet
as shown at I2, so that a waterproof container
or other explosive may, if desired, be enclosed in
a paper receptacle of suitable weight and water
for the black powder charge is provided. The
rigidness of the assembly is promoted also, and 25 resistance, for example a spirally wrapped con
more particularly continued support of the ignit
tainer arrangement. In such event, the bottom
and top of the pellet may be protected .by closures
er when Ithe wires have burned through below,
by securing the leading wires of the igniter to
in the form of what has been designated as “shot
the sides of the assembly, for example by small
gun crimps," where a heavy paper or cardboard
pieces of adhesive tape near the top of the metal 30 disc is inserted at each end of the wrapped pellet
tube on both sides, as shown at I3. Since it is
and the side paper is rolled'down at the ends to
meet the disc and to give a waterproof package.
desired that the flame be directed downward, or
at least in the direction toward which the igniter
Such a package may be further protected, if de
cavity is facing, downward direction of the flame
sired, by dipping in paraffin, or the pellet itself
is assured by introducing a body of solid material 85 may be given a parafñn coating.
at the top of ,the black powder pellet, as shown
The preferred embodimentl of our invention
at I4. A suitable material has been found to be
given in the drawing has shown a prepared elec
cast sulfur, poured onto the pellet in molten state
tric squib inserted in the internal well of the metal
and allowed to solidify there. In addition to the
tube, the squib being adapted to fire the pellet
metal container, the black powder pellet will de 40 of black powder through the metal wall of the
sirably be enclosed in a paper package.
well. We may, however, dispense with the Ysepa
While the assembly described may be used for
rate squib and load the igniting charge directly
the ignition of any desired material, we find it
into the cylindrical cavity formed by the well
particularly effective in the case of diflicultly
walls. In such case the ignition may desirably be
combustible materials, such as heavy fuel oils
of the concave-plug type, where the leading wires
which might be used in smoke pots where ob
pass through the plug and the concave end of the
scuring smokes are desired; in smudge pots such
plug toward the black powder is ñlled with the
as are employed in fruit orchards where the heat
ignition charge. The bridge wire passes through
ing effect of the smoke and gases is desired; and
the ignition charge. In an igniter for such an
in other like instances. The assembly is excel 50 assembly, the concavity would be suiiicient to hold
lently adapted for use with fuel oils, since it can
a charge sufficiently large to ñre the deilagrating
be suspended at the desired height above the oil,
explosive.
'
and an intense hot iiame from the black powder
We have described our ignition assembly at ‘
pellet is directed downward onto the oil for a
length in the foregoing. It should be under
considerable period of time, sufficient to assure 55 stood, however, that many variations may be in
permanent ignition.
troduced in the exact procedure followed or in
In the specific embodiment shown in the draw- .
the diiîerent materials and compositions used,
ing, a block or pellet of black powder was desig
without departure from the spirit of the inven
assembly in the desired position, with the igniter
entering the pellet cavity from below. The black
nated as the main explosive charge for the as
sembly.
We may use other deilagrating explo
sives, however, for example suitably shaped blocks
tion. We intend to be limited, therefore, only by
60 the following patent claims.
We claim:
y
_
of smokeless powder or other readily ignitible
1. An electric ignition assembly comprising a
compositions giving a long durable flame. It is
main charge of black powder in the form of a
essential that the deñagrating explosive be in
cohesive block, a cavity within said block, a thin
such form that a cavity is available for the elec 65 metal sheath surrounding said black powder
tric sduib. No speciñc composition of black pow
charge and in water-tight relationship therewith,
der is required, but we find satisfactory the ordi
said metal sheath being provided with an internal
nary blends of sodium nitrate, charcoal, and sul
well projecting into the cavity in the explosive,
fur, with possible small additions of other ingre
an electric initiator within said internal well, and
dients. The black powder pellet, previous to en 70 a reinforcing additional body of solid material at
closure in the metal tube, will ordinarily be
the side of the black powder charge oppositeto
wrapped in heavy paper, with igniter hole ex
that through which the cavity enters, whereby
posed.
upon initiation the direction of the flame from
Various types of electric squibs may be em
the black powder toward the side adjacentA to the
ployed as igniters for the deñagrating explosive, 75 internal cavity is favored. '
'
2,403,907
5
2. An electric ignition assembly for igniting
liquid fuel and other combustible materials, com
prising a charge of black powder in the form of
a cohesive block, a cavity within said, block, a thin
layer of metal around said black powder charge
and in water-tight relationship therewith, said
metal layer extending also in the form of an in
ternal well into the cavity in the black powder,
an electric initiator within said internal well, the
assembly being so supported that the opening of
the internal well is on the under side, the leading
wires of the electric initiator passing up along
the sides of the block of black powder so as to
6
3. An electric ignition assembly comprising a
main charge of a deñagrating explosive in the
form of a cohesive block, a cavity within said
block, a thin metal sheath surrounding said
charge and in water-tight relationship therewith,
said metal sheath being provided with an internal
well projecting into the cavity in theexplosive,
an electric initiator within said internal well, and
a reinforcing additional body of solid material on
10 the side of the explosive charge opposite to that
through which the cavity enters, whereby upon
initiation the direction of the flame from the ex
plosive toward the side adjacent tothe internal ' `
cavity is favored.
suspend the assembly in the desired position, and
a body of solid material at the top of said black 1li
powder charge adapted to direct the flame down
ward.
LAWTON A. BURROWS.
GEORGE A. NODDIN.
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