US3786752A

US3786752A - Explosive charge with improved fragmentation effect

Info

Publication number: US3786752A
Application number: US00166191A
Authority: US
Inventors: P Lingens; G Martin
Original assignee: Dynamit Nobel AG
Current assignee: Dynamit Nobel AG
Priority date: 1970-07-25
Filing date: 1971-07-26
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22
Also published as: BE770377A; FR2103286A5; DE2036977A1; NO125864B; GB1354932A

Abstract

An explosive charge and method for producing increased fragmentation per unit weight of explosive by providing hollow bodies or cavities adjacent the explosive and connected to the explosive by means of a pipe. The explosive includes a channel communicating with the pipe. Any number of hollow bodies, spaced at any desired distance from the explosive, may be employed. The channel preferably is cylindrical or annular. Each hollow body may be filled with a gas, liquid or solid medium or be under vacuum.

Description

IlnitedStates Patent Lingens et al.

[ Jan. 22, 1974 EXPLOSIVE CHARGE WITH IMPROVED FRAGMENTATION EFFECT Filed:

Inventors: Paul Lingens, Leverkusen; Garhard Martin, Troisdorf, both of Germany Assignee: Dynamit Nobel Aktiengesellschaft,

Troisdorf, Germany July 25, 1970 July 26, 1971 Appl. No.: 166,191 n V t 7 Foreign Application Priority Data Germany .2036977 US. Cl. 102/24 R, 102/67 Int. Cl. F42h 3/00, F42b 13/48 Field of Search 102/22-24, 6, 65,

References Cited UNITED STATES PATENTS Burrows 102/66 767,776 l/l904 Turner 102/22 1,554,827 9/1925 Pass l02/66 2,078,298 4/1937 White l02/22 Primary ExaminerVerlin R. Pendegrass Attorney, Agent, or Firm-Craig, Antonelli & Hill 22 Claims, 3 Drawing Figures PATENTEDJMI 2 2 1974 FIGI INVENTORS PAUL LINGENS GERHARD MARTIN RM a ATTORNEYS EXPLOSIVE'CIIARGE WITH IMPROVED FRAGMENTATION EFFECT erably higherthan the detonation velocity, i.e. such a gas flow then precedes the detonation front.

Ithas been found surprisingly that when the abovementioned gas currents of high velocity and high energy density flow into cavities, chambers or hollow bodies, a high dynamic pressure with an extremely steep slope (surge front) is builtup therein, which pressure is sufficient to splinter casings of considerable wall thickness around the cavities. In this connection, the gas flow can be conducted away from the explosive to hollow spaces disposed outside of the explosive charge, through pipelines of a corresponding strength.

Accordingly, this invention relates to an explosive device of increased fragmentation effect, characterized by a chamber; filled with an explosive from which one or more pipelines lead into cavities disposed externally of the explosive charge and surrounded by the casing for the. explosive charge.

The cavities disposed outside of the explosive charge can be filled with gaseous and/or liquid and/or solid mediums. If a solid medium, it can be in pulverized form;

Additionally, this invention relates to a process for producing an increased number of fragments in explosive devices, characterized in that gas flows are conducted, via pipelines, from the explosive device into cavities provided in the casing for the explosive charge.

Since the increase in pressure in such cavities takes place. within extremely short periods of time, the pressure stress on the casing is of a dynamic character, i.e. thestress corresponds to a very short-time pressure impulse or shock. This results in splinters or shrapnel having a great velocity, and .thus a considerable piercing effect.

In "the explosive charge, an additionally provided bore for producing the gaseous flow can exhibit any desired symmetrical as well as asymmetrical cross section or also an irregular boundary, and can vary over its length continuously or discontinuously.

As for the form of the cross section of the pipelines for conducting the gaseous flow into cavities outside of the explosive charge, the same applies as set forth above for the cross section of the bore in the explosive device... Also, i the .pipelines need not be absolutely straight; they can be, forexample, curved, or exhibit severalwknees, or any desired angle, or also the form of a spiral or helix.

With respect to the cavities into which the gas flow enters, it is of no importance whether these cavities are under a vacuum or are filled with air or gas. An amplification of the pressure for disintegrating the casing around the cavity can be effected by a filling of a flammable, explosive gas or gaseous mixture.

In general, the maximum cross section of the cavity will be adapted to that of the explosive column, with respect to the area thereof. However, it can also be larger and smaller than this cross section. The volume of the hollow space is to be adapted to the energy and brisance of the explosive and the length and cross section of the explosive column.

The gaseous stream can be conducted to the cavity through a pipe extending as much as desired into the cavity, or extending only from the surface of the explosive into the cavity. The latter possibility, however, re sults in a somewhat diminished fragmentation effect. The pipe need not be extended to the cavity absolutely in an axial orientation. Thus, for example, when the cavity is disposed geometrically with respect to the explosive column (i.e., has the same cross section), the feed pipe can be arranged outside, but in parallel, to the axis of symmetry, or it can be at an angle to this axis. Furthermore, the feed pipe for the gaseous stream, insofar as it is extended into the cavity for a specific length, can exhibit a lesser strength along this length.

In case of larger pipe lengths, it proved to be practicable to utilize a pipe sealed at the end, which pipe extends to the bottom of the cavity, and besides to make the strength of the pipe section extending into the cavity lower than that of the remainder of the feed pipe. In this arrangement, the shock pressure required for the fragmentation of the casing is produced by a damming up of the gas flow in the pipe end disposed in the cavity. As the transfer medium for the shock pressure from the pipe to the casing, preferably a liquid is employed, for example, water, oil, etc., or a medium of a powdery or solid consistency.

The invention will be explained in greater detail below with reference to the embodiments illustrated in the drawings wherein:

FIG. 1 shows a cross section of an explosive device having cavities on both sides externally of an explosive charge according to the invention;

FIG. 2 is a cross section of an explosive device exhibiting three-serially disposed cavities outside of an explosive charge according to the invention; and

FIG. 3 is a cross section of an explosive device having an annular arrangement according to the invention.

Referring to FIG. 1, cylindrical metallic body 1 is subdivided into three chambers denoted by

reference numerals

3, 4 and 5 by two partitions 2. Of these chambers, central chamber 3 contains high explosive l4, and

chambers

4 and 5 contain non-explosive gas and/or liquid and/or

solid mediums

15 and 16, respectively. Also, a pair of symmetrically-arranged bores 7 are provided in explosive chamber 3 wherein the gas flow preceding the detonation front is formed and then conducted through the pipes 10 into

chambers

4 and 5.

The ignition of the explosive 14 in the center of chamber 3 is effected by primer (or detonator) 13. If chamber 3 is large, several bores 7 may be provided in the explosive column and with the associated pipelines into the

chambers

4 and 5. When using respectively bores 7, as shown, in the direction of the two sides of chamber 3, the bores need not absolutely lie in the axis of the arrangement. Rather, the bores can also be dis posed outside of the axis in parallel or at an angle thereto.

The explosive charge illustrated in FIG. 2 consists of cylindrical metallic housing 1' subdivided into four chambers by three partitions 2. Chamber 3' is filled with a high explosive 14' and chambers 4', 5' and 6 are filled with non-explosive gas and/or liquid and/or solid mediums l5, l6 and 17. Three pairs of bores 7', 8 and 9 are provided in explosive column 3', wherein the gas currents preceding the detonation front are formed and then conducted, respectively, through pipes 10', l l and 12 into the

chambers

4, 5' and 6. By means of the primer 13', the detonative reaction of the system is initiated.

The number of the chambers without explosive need not be restricted to three, as shown in FIG. 2. The number is dependent on the length and cross section of the chamber filled with explosive. Also, a system can be provided, analogous to FIG. 1, having chambers without explosives disposed on both ends of the chamber containing the explosive. In this case, the system is ignited in the center of the explosive column. The cross sections of the individual chambers with and without explosive in the structures illustrated in FIGS. 1 and 2 can, of course, also exhibit different sizes and shapes.

It provided advantageous to fill the chambers without explosives directly adjoining the explosive column with air and the chambers disposed farther away with a transfer medium, e.g. water, oil, sand, etc. (Of course, as previously pointed out, these chambers, although designated nonexplosive, may contain a flammable, explosive gas or gaseous mixture.)

By fashioning the bores in the explosive column associated with the individual chambers without explosive of different lengths, the chronological sequence of the fragmentation of the casing of these chambers can be controlled within the time range of the reaction of the entire explosive column.

It is advisable to select the length of the bore in the explosive column associated with the first chamber in front of the explosive column to be shortest. For subsequent chambers, the lengths of the bores are preferably increased in a stepped succession.

The individual bores in the explosive column according to FIG. 2 can, but need not, be disposed absolutely symmetrical and at equal spacings from the central axis of the structure, and need not have the same diameter. The diameters of the bore can be varied within wide limits. Suitable values in this connection are those ranging between 1 and 50 mm., preferably 4 and 8 mm.

In another geometric arrangement as shown in FIG. 3 the explosive column consists of two columns 18 and 19, one inserted in the other, the former being hollow and the latter solid, and if an annular air gap 20 is provided therebetween, a gas flow is formed in this interspace during the detonative reaction. (It should be pointed out that the cross section of FIG. 2 is also representative of such an annular arrangement. Of course,

pipes

10 and 12 are cross sections of a single annular pipe and thus are preferably of the same length.) This arrangement may include not only a single annular channel but a plurality of such channels individually communicating with successively arranged separate cavities. As before, the gas flow precedes the detonation front and is accompanied by a shock wave at the tip due to air compression. If this gas flow is conducted into a cavity or chamber 21 without explosive provided at the end of the explosive column, a shock pressure is produced therein by the dammed-up gas flow, which shock pressure brings about the splintering of the easing around the chamber. In order to increase the shock pressure, it is advantageous to reduce the damming-up .space for the gas flow by continuing the solid explosive column into the cavity by means of an inert section 22. By effecting the ignition of the explosive columns in the center, cavities can be provided on both ends of the column for the formation of additional splinters. If such a column is composed of several explosive columns with corresponding annular air gaps of the type indicated above, the inner column being solid and the others hollow, it is possible to provide several cavities on both ends, similarly to the explosive charge device illustrated in FIG. 2. Each of these cavities is then associated with a specific annular air gap or channel.

The invention is not limited to annular or cylindrical gaps in the longitudinal direction of the explosive columns for the formation of the gas flow. Such flows are formed in similar explosives having any type and shape of gaps appropriately dimensioned to be utilized for the fragmentation of casings of cavities or chambers without increasing the amount of explosive.

To further amplify the nature of the invention, examples of various embodiments are presented hereinafter. In the examples, to produce the gas flow, cylindrical bodies of composition B (39.5% by weight of trinitrotoluene, 59.5% by weight of cyclotrimethylenetrinitramine and 1% by weight of wax) having a diameter of 30 mm. and a length of 140 mm. and an axial bore of a diameter of 10 mm. were employed. The explosive charges were ignited at one end with the interposition of two shaped penthrite charges of 18 g. (diameter 25 mm., length 50 mm.) by means of an aluminum cap No. 8 (a blasting cap of aluminum with a primer pellet, a primary charge of 0.3 g. of lead tricinate and a secondary charge of 0.8 g. of tetryl). The hollow chambers, cavities or bodies for these experiments were formed from two welded-together hexagonal threaded caps (1% inch; wall thickness 5 mm.; corner diameter of 58.5 mm.; height 54 and 56 mm., respectively. The transfer pipes for the flow of gas from the explosive charge to the cavity (hollow body) were made of glass, synthetic resin, copper, and iron of an inside diameter of 10 mm. (Examples l-6 only) and different wall thicknesses. Each of the hollow bodies (or cavities) was provided on one end surface with a bore disposed centrally or eccentrically. This bore served for extending the pipeline into the hollow body. The outer diameter of the pipe corresponded to that of the bore. As indicator for the fragmentation, iron barrels were utilized; the hollow bodies were disposed in the axial center line of these barrels. From the penetration of the barrel by the fragments, a conclusion could be drawn with respect to the number and size of the splinters produced by the disintegration of the hollow bodies.

EXAMPLE I A hollow body having an air filling was positioned immediately adjacent the explosive column and connected therewith by a glass pipe. to I00 fragments of up to 6 cm. resulted.

EXAMPLE 2 A hollow body with an air filling was spaced 50 mm. from the explosive column by a connecting pipe of glass. The explosion produced 80-90 fragments of up to 6 cm.

EXAMPLE 3 A hollow body with a sand filling was located mm. from the explosive column by a connecting pipe of copper. Upon detonation, 70-80 fragments of up to 6 cm. resulted:

EXAMPLE 4 A hollow body filled with water was spaced 150 mm. from the explosive column by a connecting pipe of ironuThe explosion created 70-80 fragments of up to 6 cm.

EXAMPLE 5 A hollow body with an oil filling was disposed 300 mm. from the explosive column via a glass connecting pipe. The result was 60-70 fragments of up to 8 cm.

EXAMPLE 6 A hollow body filled with water at a spacing of 450 mmyfrom the explosive column together with a glass connecting pipe, was employed. The number of fragments, which ranged up to cm., was 30-40.

EXAMPLE 7 EXAMPLE 8 Three adjacently disposed hollow bodies were pro vided, of which the first having an air filling was in direct contact with the explosive column. The two other hollow bodies, howver, were filled with water. The explosive column had a diameter of 50 mm. and three parallel, symmetrically-disposed longitudinal bores of a diameter of 8 mm. Each of the hollow bodies was in communication with, respectively, one of the three bores in the explosive charge, by means of a steel tube. The steel tubes were passed through the bodies.

In the detonative reaction of the explosive column, all three hollow bodies were separated into a large number of splinters (150-200). The fragments had a size of up to mm.

Needless to say, the devices of the examples are merely representative of embodiments of the invention and may be modified in many ways. For example, hollow bodies can be disposed on opposite ends of the explosive column with an appropriate extension of the column and a provision for central ignition.

Furthermore, the. technique of central ignition of a straight explosive column can be broadened to twodimensional or three-dimensional arrangements.

The present invention can be applied, in particular, to such explosive charges which are provided with cavitiesanyway, e.g. for the accommodation of electronic elements, such as in rocket warheads or the like. The same effect will be obtained, as previously described. The walls surrounding the cavities will be splintered so that a larger number of fragments, and thus a greater efficiency of the explosive charge for antipersonnel or like uses, result.

The present invention is not limited to the embodiments and details shown and described herein but intended to cover changes and modifications apparent to a person skilled in the art within the scope of the invention.

We claim:

1. A fragmentation device for producing splinters comprising a container formed of a material to produce splinters when subject to an explosive force, a chamber in said container filled with an explosive charge, and means for producing an increased splintering of said container, said means including at least one cavity disposed within said container outside said chamber, and channel means communicating between said chamber and said at least one cavity for conducting gas flow in response to ignition of said explosive charge from said chamber to said at least one cavity to cause increased splintering of said container.

2. A device according to claim 1 wherein said at least one cavity is filled with a medium and said container is formed of a metallic material.

3. A device according to claim 2 wherein said medium is one of a non-explosive liquid and solid.

4. A device according to claim 2 wherein said medium is one of a flammable and explosive gas.

5. A device according to claim 1 wherein said explosive charge includes at least one passageway therein which communicates with said channel means.

6. A device according to claim 5 wherein said channel means comprises at least one pipeline and said passageway is a bore.

7. A device according to claim 6 wherein said at least one pipeline and bore are substantially cylindrically shaped.

8. A device according to claim 5 wherein said channel means and said at least one passageway are annularly shaped.

9. A device according to claim 8 wherein said explosive charge comprises an inner cylindrical body and an annular body concentrically arranged therearound, said bodies being separated by the annular-shaped passageway.

10. A device according to claim 5 wherein said channel means has a sealed-off end which terminates within said at least one cavity.

11. A device according to claim 10 wherein said channel means passes substantially through said at least one cavity and the sealed-0E end thereof terminates in the vicinity of a wall of said at least one cavity.

12. A device according to claim 11 wherein said container, chamber and at least one cavity are substantially cylindrically shaped and said sealed-off end of said channel means is disposed near the wall of said at least one cavity opposite said chamber.

13. A device according to claim 2 wherein said at least one cavity comprises a plurality of cavities serially-arranged with respect to each other, the first of said cavities abutting said chamber, said channel means comprising a plurality of channels each communicating respectively between a cavity and said chamber.

14. A device according to claim 2 wherein said at least one cavity includes at least two cavities, each disposed on opposite sides of said chamber.

15. A device according to claim 14 further comprising a central primer disposed within said explosive charge between said cavities.

16. A process for the production of an increased number of splinters of a fragmentation device having a container formed of a material to produce splinters when subjected to an explosive force and having an explosive charge filling a chamber disposed within the container, comprising producing an increased splintering of the container by disposing at least one cavity within the container outside of the chamber, igniting the explosive charge within the chamber, and conducting the gas flow resulting from the ignition of the explosive charge from the chamber into the at least one cavity to cause increased splintering of the container.

17. A process according to claim 16 wherein said gas flow is channeled through a narrow passageway and expanded into said at least one cavity.

18. A process according to claim 16 wherein said gas flow is directed through at least one pipeline into said at least one cavity.

19. A process according to claim 18 wherein said gas flow is conducted through at least one bore in said explosive charge into said at least one pipeline.

20. An explosive device producing increased fragmentation upon detonation comprising a substantially cylindrical fragmentable container, a chamber including an outer annular explosive body and an inner cylindrical explosive body disposed within said outer annular explosive body, said explosive bodies being separated by an annular-shaped passageway, at least one cylindrical cavity disposed within said container and abutting said chamber and channel means communicating between the annular-shaped passageway and said at least one cavity for conducting gas flow from said chamber to said at least one cavity in response to ignition of said explosive bodies for causing increased fragmentation of said container.

21. An explosive device according to claim 20 wherein said channel means is a cylindrically shaped pipe having one end communicating with the annularshaped passageway while the other end is sealed-off.

22. An explosive device according to claim 21 wherein an inert, non-explosive cylindrical body of a diameter corresponding to the diameter of said inner cylindrical explosive body is disposed concentrically inside said channel means and abuts at opposite ends thereof said inner cylindrical explosive body and the closed-off end of said pipe.

Claims

11. A device according to claim 10 wherein said channel means passes substantially through said at least one cavity and the sealed-off end thereof terminates in the vicinity of a wall of said at least one cavity.

21. An explosive device according to claim 20 wherein said channel means is a cylindrically shaped pipe having one end communicating with the annular-shaped passageway while the other end is sealed-off.