Off-axis annular precision initiation charge

Patent metadata

Field	Value
Publication number	US-10267603-B2
Application number	US-201715659422-A
Country	US
Kind code	B2
Filing date	Jul 25, 2017
Priority date	Jul 25, 2017
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

One embodiment provides an apparatus. The apparatus includes a substrate body that includes a top end, an opposing bottom end and a curved outer surface positioned there between, and a clear sight bore aperture centered at a longitudinal axis of the substrate body. The apparatus further includes a trunk line aperture defined in the outer surface of the substrate body. The trunk line aperture has a first end positioned at a top end of the substrate body, off-center from the longitudinal axis. The first end of the trunk line aperture is configured to couple to a detonator. The apparatus further includes a plurality of helical track apertures defined in the outer surface of the substrate body. A respective first end of each helical track aperture is coupled to the trunk line aperture. The apparatus further includes a plurality of termination apertures defined in the outer surface of the substrate body adjacent the bottom end of the substrate body. One termination aperture is coupled to the trunk line aperture at a second end of the trunk line aperture. The second end is opposing the first end and each remaining termination aperture is coupled to a respective helical track aperture. The trunk line aperture, the plurality of helical track apertures and the plurality of termination apertures are configured to contain an explosive material.

First claim

What is claimed is:

1. An apparatus comprising:
a substrate body comprising a top end, an opposing bottom end and a curved outer surface positioned there between;
a clear sight bore aperture centered at a longitudinal axis of the substrate body;
a trunk line extending along the substrate body, the trunk line having a first end positioned at a top end of the substrate body, off-center from the longitudinal axis, the first end of the trunk line configured to couple to a detonator;
a plurality of helical tracks extending along the substrate body, a respective first end of each helical track coupled to the trunk line; and
a plurality of terminations adjacent the bottom end of the substrate body, one termination coupled to the trunk line at a second end of the trunk line, the second end opposing the first end and each remaining termination coupled to a respective helical track,
the trunk line, the plurality of helical tracks and the plurality of terminations containing an explosive material.

2. The apparatus of claim 1 , further comprising a plurality of channel apertures defined in the outer surface of the substrate body, each channel aperture positioned adjacent at least one helical track.

3. The apparatus of claim 1 , further comprising an end cap, a tamper and an explosive booster,
the end cap configured to couple to the substrate body, the end cap defining an end cap aperture configured to align with the clear sight bore aperture when the end cap is coupled to the substrate body, the end cap further defining a detonator aperture configured to receive the detonator, the detonator configured to couple to a first end of the trunk line when the end cap is coupled to the substrate body,
the tamper configured to contain an explosive initiation charge within the tamper between the end cap and a main explosive charge, and
the explosive booster configured to couple to the plurality of terminations and to the substrate body at the bottom end of the substrate body.

4. The apparatus of claim 1 , wherein each termination has a semicircular shape bounded by a curved portion and a termination bottom surface and a number of terminations is between six and thirty.

5. The apparatus of claim 1 , wherein a target range of travel times for a plurality of paths between a trunk line first end positioned at the top end of the substrate body and a plurality termination bottom surfaces for a plurality of explosive wave fronts is less than 200 nanoseconds.

6. An explosive system comprising:
a main explosive charge; and
an off-axis annular precision initiation charge (APIC) assembly coupled to the main explosive charge, the off-axis APIC assembly comprising:
a substrate body comprising a top end, an opposing bottom end and a curved outer surface positioned there between,
a clear sight bore aperture centered at a longitudinal axis of the substrate body,
a trunk line having a first end positioned at the top end of the substrate body, off-center from the longitudinal axis, the first end of the trunk line configured to couple to a detonator,
a plurality of helical tracks, a respective first end of each helical track coupled to the trunk line, and
a plurality of terminations positioned adjacent the bottom end of the substrate body, one termination coupled to the trunk line at a second end of the trunk line, the second end opposing the first end and each remaining termination coupled to a respective helical track,
an explosive booster coupled to the plurality of terminations and to the substrate body at the bottom end of the substrate body,
the trunk line, the plurality of helical tracks and the plurality of terminations containing an explosive material.

7. The system of claim 6 , wherein the off-axis APIC assembly further comprises a plurality of channel apertures defined in the outer surface of the substrate body, each channel aperture positioned adjacent at least one helical track.

8. The system of claim 6 , wherein the explosive booster extends from the outer surface of the substrate body to one half a radius of a top end of the main explosive charge.

9. The system of claim 6 , wherein the main explosive charge comprises an explosive region and a liner, the explosive region defining an explosive bore aperture and the liner defining a liner aperture, the explosive aperture and liner aperture aligned with the clear sight bore aperture.

10. The system of claim 6 , wherein the main explosive charge is a shaped charge comprising a conical liner and a shaped charge explosive region positioned on an outer surface of the conical liner, the conical liner defining a cone angle and the shaped charge explosive region has a flare angle measured between the outer surface of the conical liner and an outer surface of the shaped charge explosive region.

11. The system of claim 10 , wherein the flare angle is in the range of zero to one half of the cone angle.

12. The system of claim 11 , wherein a net explosive weight (N.E.W.) of the shaped charge is related to the flare angle.

13. The system of claim 10 , further comprising a liner ring coupled to the conical liner at a bottom end of the conical liner and the bottom end of the conical liner corresponds to a charge diameter.

14. The system of claim 13 , wherein the shaped charge is configured to be positioned twelve to eighteen charge diameters from a target.

15. The system of claim 6 , wherein the main explosive charge is an explosively formed projectile (EPF) comprising a crescent liner and an EFP explosive region, the crescent liner positioned at a bottom end of the EFP.

16. The system of claim 15 , wherein the EFP explosive region comprises a first explosive portion positioned adjacent a bottom end of the off-axis APIC assembly and a second explosive portion positioned between the first explosive portion and the crescent liner, a diameter of the second explosive portion greater than or equal to a diameter of the first explosive portion, the diameter of the first explosive portion corresponding to a diameter of the substrate body.

17. The system of claim 15 , wherein the crescent liner comprises a liner curved portion and a liner ring portion, the liner curved portion having a crescent shaped cross section.

18. The system of claim 17 , wherein the crescent liner comprises a liner ring slot.

19. The system of claim 17 , wherein the EFP is configured to form a slug that impacts a target, the slug formation related to a liner geometric parameter, the liner geometric parameter selected from the group comprising a crescent liner outer surface outer radius (R 1 ), a crescent liner inner surface inner radius (R 2 ), a liner ring slot dimension and a liner ring slot position in the liner ring portion.

Assignees

• Southwest Res Inst

Inventors

• Marshall Andrew J
• Smith Thad C
• Weiss Carl E
• Herring Joseph M

Classifications

• F42D1/08

  Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor · CPC title

• F42B1/028 Primary

  characterised by the form of the liner · CPC title