US3092025A - Detonating device - Google Patents

Description

June 4, 1953 J. R. HRADEL ETAL 3,092,025

DETONATING DEVICE Filed Aug. 11, 1960 La 2 Wm.

Joseph R. Hraa'e/ BY Michae/E Hraa'e 3,092,025 DETONATIN G DEVICE Joseph R. Hradel and Michael F. Hradel, Mount Pleasant,

Mich, assignors to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed Aug. 11, 1960, Ser. No. 48,958 2 Claims. (Cl. 102-44) The present invention relates to an apparatus for the detonation of explosives. More particularly the invention relates to a detonating device employing a shaped charge to accomplish detonation which device is extremely positive in action and simplifies prior detonating procedures.

This is a continuation in part of our copending application Serial No. 750,481, filed July 23, 1958, now abandoned.

It is known that the Munroe jet, or conic shaped explosive charge, is efiicient in the detonation of explosive materials, even those materials having relatively low sensitivity, so long as the projection of the principal shock wave substantially intersects a body of explosive material. Shot prop-ogation is materially enhanced and low sensitivity explosives are rendered substantially as elfective as comparable charges of high explosive material.

For simple blasting of vertical bore holes as in mining and quarrying operations, the problem has been one of bringing the advantages of such detonation to a field where a mass of low sensitivity explosive material in liquid, semi-liquid or granular form is placed in the bore hole with or without appropriate top tamp. The customary procedures have involved high explosives such as sensitive trinitrotoluene, composition C, Nitrogel, dynamite and the like, and frequently rendered further sensitive by sensitizers of various types. This has been required in order that substantially complete detonation will be obtained. Such operations are thus delicate and very dangerous, as well as expensive and the placing of actual detonators in the mass has required the very keenest of care to assure against premature detonation and to insure substantially complete use of the explosive charge. Detonation has been accomplished by the uniform distribution of fused detonators in the mass, or by the use of torpedoes containing single or plural detonators or caps intimately associated with a primer charge of extremely sensitive material. Even using these methods the propagative eifect has been poor and very dangerous explosive residue has hampered the operations following the actual blast.

The principal object of the present invention is to provide a directionally convertible initiating device or shaped charge detonator holder for positioning an axially oriented deton-ator element.

Another object of the present invention is to provide a device for axial detonation that is simple and economical to use and which greatly facilitates rigging of the shooting lines.

Still another object of the present invention is to provide a cheap and frangible encasement for a shaped charge initiator which encasement is fluidproof, contains an oriented shaped charge, and secures a charge initiator in biased relationship to the base of the shaped charge despite applied tension on the shooting lines.

A further object of the present invention is to provide an initiating device useful for detonation of normally insensitive and hard to detonate explosive materials.

Still another object is to provide a device requiring no elaborate equipment to use and which is oriented by means of the positioning of the shooting'lines.

Other objects and advantages will be increasingly apparent to those skilled in the art from the accompanying drawings and the detailed description presented hereinafter.

In the drawings:

FIGURE 1 is a perspective view of the device of the present invention showing the location of the shaped charge in the case.

FIGURE 2 is a full section view of the device of the present invention taken by longitudinally splitting the device shown in FIGURE 1, and showing the device of the present invention rigged for directing the principal shock wave of the shaped charge in a downward direction.

FIGURE 3 is a side elevation view of the device of the present invention illustrating the rigging of the device for suspension in a bore hole adjacent the bottom of a column of explosive and rigged for directing the principal shock wave of the shaped charge in an upward direction.

It has now been found that (1) excellent detonations with maximum propagative eliects and (2) good dynamic control by the detonator over tamping can be achieved by placing a shaped charge into substantial contact with an explosive mass in such a manner that the principal axis of detonation of the shaped charge corresponds to the longitudinal axis of the explosive mass. The positioning of the shaped charge in such an oriented relationship to an explosive mass is greatly simplified by providing a receptacle for retaining the shaped charge member.

One embodiment of a shaped charge positioning device is illustrated by FIGURES l-3 inclusive.

A shaped charge 11 is provided having a block of high explosive material 11, such as RDX, encased within a metal lining 12. The explosive 11 is formed to have a conical depression or cone 13 which cone 13 is faced with a thin metal lining 14.

The shaped charge 10 is provided with a cylindrical metal tip 15 projecting normally outward from the back side or base 16 of the charge 10 opposite the apex of the cone 13. This tip 15 defines two openings, 17 and 18, one of which openings 17 passes laterally through the tip 15' just above the initiator promotor 16a on the back side of the lining 12 of the charge 10, and the other opening 18 which is directed vertically downward (longitudinally) along the center axis of the tip and intersects hole 17. These holes are of a preselected size to accommodate conventional initiating means, for example, a strand of Primacord or a conventional electric blasting cap.

The shaped charge 10 is encased by a receptacle or case 19. This case 19 is cylindrical in external shape over its forward hollow compartment or cavity 2% and is tapered inwardly at the back end leading into a tail compartment 21 comprising a rearward tubular extension of the section 20. This tail section or cavity 21 is of smaller diameter than the section 26 and is partially separated from the section 2%. The tail section 21 has a partial longitudinal slot 22 through the wall at one spot. A plurality of fins 23 jut radially outward to a distance substantially equal to the diameter of the forward section 20 starting at the upper end of the tail section 21 and extend longitudinally from the end of the tail section 21 to join the tapered portion of the forward section 20.

The section 21B is provided with an opening 24 through the reduced section below the tubular tail section 21. Further, an annular opening 25 is incorporated into the structure which separates the lower end of the tail section21 and the forward section 20.

The shaped charge 19 is positioned inside the receptacle 19 against the wall as so that the principal axis of the conical depression 13 in the shaped charge coincides with 3 the principal or longitudinal axis of the forward section 20 of the case 19. Further the cylindrical tip 15 of the shaped charge protrudes through the opening 24 in the back of the forward section 20 of the receptacle or case 19 and substantially fills the annular opening 25 between the forward section 20 and tail section 21 of the case.

A substantially cylindrical cover or cap 27 is provided to complete the assembly. The cap 27 is so designed to mate, by means of a slip fit, with the open end 28 of the case 19. The projecting wall 29 of the cap 27 is of such a length that upon assembly it slides into the forward section 29 of case 19 along the wall 26 and makes contact with the outer conical edge 30 of the shaped charge 19 thereby helping to hold the charge 10 in the desired alignment. The cap 27 has a fiat bottom 31 containing a forwardly projecting integral lug 32 on the longitudinal axis of the cap.

The lug 32 and one of the fins 23 provide rigging hangers 33 and 34 respectively for stringing firing lead lines from an initiator for the charge 10. The simplest form of the hanger 33 and 34 are merely openings defined by the receptacle stock of the lug 32 and fin 23.

In assembly of the device of the instant embodiment the shaped charge 10 is positioned in the case 19 and advantageously secured, as by cementing, into position against the wall 26, as previously indicated. The nose piece or cap 27 and receptacle 19 containing the so held shaped charge 10 are also made into an integral unit after assembling by cementing at the joints thereby to make the device fluidproof and moisture proof for use.

The case 19 and cap 27 can be made from a number of materials, e.g., polystyrene, glass, diecast metal, ceramics, polyethylene, natural rubber, synthetic rubber, resin, and the like utilizing conventional fabrication technique, i.e., molding, extrusion, etc. Preferably this holder for the shaped charge 10 will be prepared by molding the case 19 and cap 27 from a frangible material, such as high impact styrene, which still offers ruggedness with respect to handling and use, economy and simplicity of construcnon.

In utilizing the device of the present invention to detonate an explosive load as in a bore hole, for example the initiation of the shaped charge 10 can be accomplished by a variety of means. For example, an initiator, such as an electrical blasting cap 35 can be inserted into the tubular tail section 21 of the case 19 where it fits snugly. The head of the blasting cap 35 is pushed down through the tubular member 21 and into the vertical hole 18 in the cylindrical tip of the shaped charge 10 thereby making contact with the initiator promoter 16a in the back of the lining 12 of the shaped charge 10 immediately behind the apex of the cone 13. The lead wires 36a36b of the cap can be passed through opening 34 in the fin and from thence to a firing device (not shown). By stringing the lead wires 36a-36b in this manner and upon lowering the detonator device into a bore hole onto an explosive mass or by placing it in contact with the top of an explosive mass the device is positioned so that upon detonation the principal axis of detonation is directed downward through the explosive and along its principal axis.

Alternatively, the lead wires 36a36b can be passed through the slot 22 along the side of the case 19 and cap 27, through the opening 33 in the lug 32 and to a firing device. When wired in this manner, the detonator device can be lowered adjacent to the bottom of a bore hole, for example, where it will come to rest with the principal axis of detonation of the shaped charge 10 pointing upward along the longitudinal axis of the hole. An explosive mass can then be placed in the hole, around and on top of the .detonator. Effective detonation of the mass from the bottom up is thereby achieved upon initiation of the detonator.

In FIGURE 3, initiation of the detonator by a strand of Primacord 37 is illustrated. In this instance, the Primacord is passed through the horizontal opening 17 in the cylindrical tip 15 of the shaped charge. One end of the strand is knotted 38 and the other end passed through the opening 33 in the lug 32 and on to the firing device. Insertion of the Primacord in this manner, as with the blasting cap initiation when similarly strung, causes the principal axis of detonation of the shaped charge 10 to be directed upward when the device is lowered into a bore hole, for example. Alternatively, for downwardly directed positioning of the principal axis of detonation of the shaped charge 10, the Primacord 37 will be passed through the opening 34 in the tail fin 23 and on to the detonator as shown for the blasting cap wires in FIG- URE 2.

With the Primacord initiation it is understood further, for example, that one end of the Primacord can be passed through the hole 17, and the other through the opening 33 in the lug 32 or opening 34 in the tail fin 23, and these then knotted or joined above the case thereby holding the case by a loop.

The entire detonation device including case 19, cap 27, shaped charge 10 and initiator is sufiiciently light in weight so that the leads 3611-361; of the blasting cap 35 or the Primacord 37 serves as a satisfactory shooting line. Further, the described rigging seats the charge 10 securely against the wall and back side of the case 19. Also, separation of the initiator from the charge is prevented when tension occurs in the lead lines.

Various modifications can be made in the apparatus of the present invention for it is understood that we limit ourselves only as defined in the appended claims.

We claim: I

l. A shaped charge receptacle for retaining a prepositioned shaped charge comprising; a molded cylindrical shell defining a forward shaped charge receiving compartment and a smaller diameter rearward extending tubular partially slotted initiator compartment, said compartments separated by an open annular opening but joined through a plurality of fins radially extending from said smaller diameter tubular initiator holding compartment and extending longitudinally to said shaped charge receiving compartment, one of said fins defining an opening therethrough, and, a lug extending from the front and along the axis of said cylindrical shell and defining an opening transverse of the axis of said shell.

2. In a device for accomplishing detonation of an explosive, the combination comprising; a two member frangible case, the first member of said case defining a forward cavity and a smaller diameter rearward extending tubular compartment separated by an open annulus and the second member of said case being a cover which slidably engages the forward cavity of said first member, integral fins extending rearwardly from said first member and radially extending from said smaller diameter tubular compartment, a pair of hanger member, one being a lug defining an opening therein extending outwardly from the face of the cover member of said case and the other hanger being an opening defined in one of said radial fins, a shaped explosive charge of a mass of high explosive encased within a metal lining, said high explosive being in the form of a hollow cone, the metal lining encasing said explosive having a cylindrical tip projecting outwardly therefrom on the side opposite the apex of the cone of said high explosive, said shaped explosive charge secured in said forward cavity of said first member of said case and having said tip projecting from the metal lining covering said explosive extending into the annulus, said tip defining longitudinal and lateral openings for an initiator, an initiator insertable into said openings and secured through its firing lead to said case by means of said hangers, and, seal means fluidproofing said case and securing it in assembled relationship.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Jones May 19, 1914 Sweetman May 25, 1954 Allen et al Sept. 14, 1954 6 McCullough July 31, 1956 Alderson Mar. 26, 1957 Brandt May 28, 1957 Crawford Jan. 20, 1959 Griffith et al. July 25, 1961

Claims (1)

1. A SHAPED CHARGE RECEPTACLE FOR RETAINING A PREPOSITIONED SHAPED CHARGE COMPRISING; A MOLDED CYLINDRICAL SHELL DEFINING A FORWARD SHAPED CHARGE RECEIVING COMPARTMENT AND A SMALLER DIAMETER REARWARD EXTENDING TUBULAR PARTIALLY SLOTTED INITIATOR COMPARTMENT, SAID COMPARTMENTS SEPARTED BY AN OPEN ANNULAR OPENING BUT JOINED THROUGH A PLURALITY OF FINS RADIALLY EXTENDING FROM SAID SMALLER DIAMETER TUBULAR INITIATOR HOLDING COMPARTMENT AND EXTENDING LONGITUDINALLY TO SAID SHAPED CHARGE RECEIVING COMPARTMENT, ONE OF SAID FINS DEFINING AN OPENING THERETHROUGH, AND, A LUG EXTENDING FROM THE FRONT AND ALONG THE AXIS OF SAID CYLINDRICAL SHELL AND DEFINING AN OPENING TRANSVERSE OF THE AXIS OF SAID SHELL.

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