CA1146803A - Cartridge end closure using a disc of resilient, closed-cell foamed synthetic plastics material - Google Patents
Cartridge end closure using a disc of resilient, closed-cell foamed synthetic plastics materialInfo
- Publication number
- CA1146803A CA1146803A CA000342099A CA342099A CA1146803A CA 1146803 A CA1146803 A CA 1146803A CA 000342099 A CA000342099 A CA 000342099A CA 342099 A CA342099 A CA 342099A CA 1146803 A CA1146803 A CA 1146803A
- Authority
- CA
- Canada
- Prior art keywords
- cartridge case
- case
- disc
- cartridge
- closure disc
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B3/00—Blasting cartridges, i.e. case and explosive
- F42B3/24—Cartridge closures or seals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D39/00—Closures arranged within necks or pouring openings or in discharge apertures, e.g. stoppers
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Buffer Packaging (AREA)
- Packaging Of Annular Or Rod-Shaped Articles, Wearing Apparel, Cassettes, Or The Like (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
Abstract:
Cartridge end-closure A tubular explosives cartridge having at least one end closed by a transverse closure disc of resilient closed-cell foamed synthetics plastics material, for example, foamed polyethylene, the disc having an uncompressed diameter greater than the internal diameter of the tubular cartridge case.
The closure provides a waterproof seal without preventing communication of detonation between cartridges and may be readily pierced for the in-sertion of a detonator. When the closure consists of nitrogen blown polyethylene, it does not increase the risk of firedamp ignition in coal mines.
Cartridge end-closure A tubular explosives cartridge having at least one end closed by a transverse closure disc of resilient closed-cell foamed synthetics plastics material, for example, foamed polyethylene, the disc having an uncompressed diameter greater than the internal diameter of the tubular cartridge case.
The closure provides a waterproof seal without preventing communication of detonation between cartridges and may be readily pierced for the in-sertion of a detonator. When the closure consists of nitrogen blown polyethylene, it does not increase the risk of firedamp ignition in coal mines.
Description
~1468~3 Cartridge end-closure This invention relates to exnlosive cartridges and to a method of closing an end of an explosive cartridge. The invention is especially advantageous ior cartridged nitroglycerine gelatinous explosives and aqueous slurry explosive compositions.
Explosive compositions have for many years been packaged in rigid tubular cardboard or tough plastics containers, the ends o~ the containers being closed by inwardly crimping a portion of the container wall or by covering the end with a thin cardboard or plastics disc. This form o~ closure is not water resistant and the cartridges were not suitable ~or use in wet surroundings unless the explosive composition was itsel~ water resistant.
When employed in cartridged form in a wet drill-hole for rock blasting, deformable, water sensitive explosive com~osition such as aqueous slurry explosives are usually pac~ed in closed waterproo~ bags of thin flexible synthetic plastics such as polyethylene and the bags are placed inside rigid or tough tubular containers of cardboard or plastics material. Because of the need to seal the plastics inner bags and plug the ends of the rigid containers there is often excessive space between the explosive contents of adjacent cartridges so that with relatively insensitive explosives in small diameters the detonation may fail to propagate between adjacent cartridges in file.
There is therefore a requirement for a cartridge case to protect the ex~losive composition from ambient water without unduly interfering with the communication of detonation between cartridges. Moreover for cartridges to be used in coal mines it is desirable that the materials used in the cartridge case should not increase the risk of igniting firedamp in the vicinity of the explosion.
Accordingly it is an object of this invention to provide an improved waterproof end-closure for a rigid cartridge case.
In accordance with this invention at least one end of a tubular cartridge case is closed by a trans-verse closure disc of resilient closed-cell foamed synthetic ~lastics material, said disc having an uncompressed diameter greater than the internal diameter of the tubular case. The dimensions of the closure disc may be readily chosen such that the disc resilience causes sufficient outward radial pressure against the case that the case is sealed against the ingress of ambient water.
The cartridge case end may be plain but more reliable retention of the closure disc is obtained if ~5 the end rim of the tubular case is ~olded over internally to form an end bead, or if one or more internal projections, ~or example, one or more cannelures are formed in the end ~ortion of the case to engage the closure disc and hold it in position.
The de~ree of foaming and the thickness of the closure disc are not narrowly critical, the practical re~uire~ent being that the foamed material should be sufficiently resilient to provide the required seal.
Thus a foamed material having a density of 30 to 70 kg/m3 is generally satisfactory and discs having a thickness to uncompressed diameter ratio of 1:2.5 to 1:5 are generally sufficiently robust to provide an adequate seal, to resist displacement and to be readily pierced for the insertion of a detonator in the field.
~ or cartridges to be used in mines where incendive gases are present, it is preferred that the 5 closure disc should be made from foamed polyethylene, preferably blown with an inert gas, for example, nitrogen. A convenient, easily made closure disc is one shaped by stamping from a sheet of foa~,ed plastics material, for example, closed-cell foamed polyethylene commercially available under the name "Plastazote"
(Registered Trade Mark) from Bakelite Xylonite Limited.
The uncompressed diameter of the disc is pref-erably 10 to 25~o greater than the internal diameter o~ the cartridge case. Thus for a case having an internal diameter of 30 mm a disc having a diameter of 33 to 37.5 mm, pre~erabl~ 35 mm is convenient.
The thickness o~ the disc in this case is conveniently 7 to 12 mm.
The cartridge case may conveniently be made from any of the materials commonly used for that purpose, for example, cardboard, helically wound multi-ply paper or extruded plastics material.
The invention is further illustrated by the cartridge end-closures illustrated in the accompanying drawings wherein Figs. 1 to 4 inclusive are longitudinal medial sections of cartridge ends closed in accordance with the invention. In the drawings like parts are depicted by the same numeral.
In the cartridge end of Fig. 1 a disc 11 of resilient closed cell polyethylene is inserted into an end portion of a cartridge case 12. In its normal state the disc 11 has a greater diameter than the internal diameter of the cartridge case 12 and is compressed to permit its insertion into the cartridge case. Because of its resilient nature the disc 11 presses tightly around its periphery against the ~1468~)3 case 12 and seals the case against the ingress of water, so that the explosive contents of the cartridge, which may advantageously be aqueous slurry explosive or a powdered explosive based on ammonium nitrate, are protected from ambient water. The other end of the cartridge case 12 may if desired be closed with a similar closure although any other waterproof closure may be used.
In Fig. 2 the end of the cartridge case 12 is turned over to form a top bead 13 against which the disc 11 abuts so that the disc is more difficult to displace from the case 12 by distortion of the case.
In the cartridge end of Fig. 3 the cartridge case is shaped at the end by two cannelures 14 and 15 between which the disc 11 is positively located.
The cartridge end o~ Fig. 4 is a ~odification o~
the cartridge end of Fig. 3 in which the mouth end of the cartridge case 12 is extended beyond the cann-elure 14 to provide an internally threaded portion 16which is adapted to receive an externally threaded portion of an end of an adjacent cartridge. By screwing the cartridge ends together a ~ile o~
cartridges may be readily assembled ~or loading in a borehole.
Explosive compositions have for many years been packaged in rigid tubular cardboard or tough plastics containers, the ends o~ the containers being closed by inwardly crimping a portion of the container wall or by covering the end with a thin cardboard or plastics disc. This form o~ closure is not water resistant and the cartridges were not suitable ~or use in wet surroundings unless the explosive composition was itsel~ water resistant.
When employed in cartridged form in a wet drill-hole for rock blasting, deformable, water sensitive explosive com~osition such as aqueous slurry explosives are usually pac~ed in closed waterproo~ bags of thin flexible synthetic plastics such as polyethylene and the bags are placed inside rigid or tough tubular containers of cardboard or plastics material. Because of the need to seal the plastics inner bags and plug the ends of the rigid containers there is often excessive space between the explosive contents of adjacent cartridges so that with relatively insensitive explosives in small diameters the detonation may fail to propagate between adjacent cartridges in file.
There is therefore a requirement for a cartridge case to protect the ex~losive composition from ambient water without unduly interfering with the communication of detonation between cartridges. Moreover for cartridges to be used in coal mines it is desirable that the materials used in the cartridge case should not increase the risk of igniting firedamp in the vicinity of the explosion.
Accordingly it is an object of this invention to provide an improved waterproof end-closure for a rigid cartridge case.
In accordance with this invention at least one end of a tubular cartridge case is closed by a trans-verse closure disc of resilient closed-cell foamed synthetic ~lastics material, said disc having an uncompressed diameter greater than the internal diameter of the tubular case. The dimensions of the closure disc may be readily chosen such that the disc resilience causes sufficient outward radial pressure against the case that the case is sealed against the ingress of ambient water.
The cartridge case end may be plain but more reliable retention of the closure disc is obtained if ~5 the end rim of the tubular case is ~olded over internally to form an end bead, or if one or more internal projections, ~or example, one or more cannelures are formed in the end ~ortion of the case to engage the closure disc and hold it in position.
The de~ree of foaming and the thickness of the closure disc are not narrowly critical, the practical re~uire~ent being that the foamed material should be sufficiently resilient to provide the required seal.
Thus a foamed material having a density of 30 to 70 kg/m3 is generally satisfactory and discs having a thickness to uncompressed diameter ratio of 1:2.5 to 1:5 are generally sufficiently robust to provide an adequate seal, to resist displacement and to be readily pierced for the insertion of a detonator in the field.
~ or cartridges to be used in mines where incendive gases are present, it is preferred that the 5 closure disc should be made from foamed polyethylene, preferably blown with an inert gas, for example, nitrogen. A convenient, easily made closure disc is one shaped by stamping from a sheet of foa~,ed plastics material, for example, closed-cell foamed polyethylene commercially available under the name "Plastazote"
(Registered Trade Mark) from Bakelite Xylonite Limited.
The uncompressed diameter of the disc is pref-erably 10 to 25~o greater than the internal diameter o~ the cartridge case. Thus for a case having an internal diameter of 30 mm a disc having a diameter of 33 to 37.5 mm, pre~erabl~ 35 mm is convenient.
The thickness o~ the disc in this case is conveniently 7 to 12 mm.
The cartridge case may conveniently be made from any of the materials commonly used for that purpose, for example, cardboard, helically wound multi-ply paper or extruded plastics material.
The invention is further illustrated by the cartridge end-closures illustrated in the accompanying drawings wherein Figs. 1 to 4 inclusive are longitudinal medial sections of cartridge ends closed in accordance with the invention. In the drawings like parts are depicted by the same numeral.
In the cartridge end of Fig. 1 a disc 11 of resilient closed cell polyethylene is inserted into an end portion of a cartridge case 12. In its normal state the disc 11 has a greater diameter than the internal diameter of the cartridge case 12 and is compressed to permit its insertion into the cartridge case. Because of its resilient nature the disc 11 presses tightly around its periphery against the ~1468~)3 case 12 and seals the case against the ingress of water, so that the explosive contents of the cartridge, which may advantageously be aqueous slurry explosive or a powdered explosive based on ammonium nitrate, are protected from ambient water. The other end of the cartridge case 12 may if desired be closed with a similar closure although any other waterproof closure may be used.
In Fig. 2 the end of the cartridge case 12 is turned over to form a top bead 13 against which the disc 11 abuts so that the disc is more difficult to displace from the case 12 by distortion of the case.
In the cartridge end of Fig. 3 the cartridge case is shaped at the end by two cannelures 14 and 15 between which the disc 11 is positively located.
The cartridge end o~ Fig. 4 is a ~odification o~
the cartridge end of Fig. 3 in which the mouth end of the cartridge case 12 is extended beyond the cann-elure 14 to provide an internally threaded portion 16which is adapted to receive an externally threaded portion of an end of an adjacent cartridge. By screwing the cartridge ends together a ~ile o~
cartridges may be readily assembled ~or loading in a borehole.
Claims (12)
1. A tubular blasting cartridge case for use in blasting operations wherein a plurality of such cart-ridges are disposed in file, said case being closed at least at one open end by a transverse closure disc of resilient closed-cell foamed synthetics plastics material, said disc having an uncompressed diameter greater than the internal diameter of the tubular case.
2. A cartridge case as claimed in Claim 1 wherein the closure disc has dimensions such that the disc resilience causes sufficient outward radial pressure against the case that the case is sealed against the ingress of ambient water.
3. A cartridge case as claimed in Claim 1 wherein the end rim of the tubular case is folded over inter-nally to form an end bead to retain the closure disc in the cartridge case end.
4. A cartridge case as claimed in Claim 1 wherein one or more cannelures are formed in the end portion of the case to engage the closure disc and hold it in position.
5. A cartridge case as claimed in Claim 1 wherein the foamed material has a density of 30 to 70 kg/m3.
6. A cartridge case as claimed in Claim 1 wherein the closure disc has a thickness to uncompressed diameter of 1:2.5 to 1:5.
7. A cartridge case as claimed in Claim 1 wherein the synthetics plastics material of the closure disc is foamed by blowing with an inert gas.
8. A cartridge case as claimed in Claim 1 wherein the closure disc has been shaped by stamping from a sheet of foamed plastics material.
9. A cartridge case as claimed in Claim 8 wherein the closure disc has been stamped from a sheet of closed-cell foamed polyethylene.
10. A cartridge case as claimed in Claim 1 wherein the uncompressed diameter of the closure disc is 10 to 25% greater than the internal diameter of the cartridge case.
11. A cartridge case as claimed in Claim 1 wherein the casing material is selected from the group consist-ing of cardboard, helically wound multi-ply paper and extruded plastics material.
12. An explosive cartridge comprising a casing as claimed in Claim 1 containing an explosive composition selected from the group consisting of gelatinous nitroglycerine explosive compositions, aqueous slurry explosive compositions and ammonium nitrate powder explosive compositions.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7901348 | 1979-01-15 | ||
| GB7901348 | 1979-01-15 | ||
| GB7937952A GB2040412B (en) | 1979-01-15 | 1979-11-01 | Cartridge end-closure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1146803A true CA1146803A (en) | 1983-05-24 |
Family
ID=26270224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000342099A Expired CA1146803A (en) | 1979-01-15 | 1979-12-14 | Cartridge end closure using a disc of resilient, closed-cell foamed synthetic plastics material |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0013473B1 (en) |
| JP (1) | JPS5596899A (en) |
| AU (1) | AU525543B2 (en) |
| CA (1) | CA1146803A (en) |
| GB (1) | GB2040412B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60181600U (en) * | 1984-05-08 | 1985-12-02 | 旭化成株式会社 | safety jacket |
| AUPP225298A0 (en) * | 1998-03-10 | 1998-04-02 | Orica Australia Pty Ltd | Method and device for loading blastholes |
| US8006622B2 (en) | 2006-11-07 | 2011-08-30 | Orica Explosives Technology Pty Ltd | Protector for detonator, and method of use |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE183441C (en) * | ||||
| BE422629A (en) * | 1938-04-15 | |||
| US2345887A (en) * | 1940-04-05 | 1944-04-04 | Hercules Powder Co Ltd | Method of sealing containers |
| US2930275A (en) * | 1955-11-15 | 1960-03-29 | American Cyanamid Co | Method of sealing spirally wound dynamite containers |
| US2916995A (en) * | 1956-05-17 | 1959-12-15 | Du Pont | Tamping plug |
| US2996232A (en) * | 1956-09-14 | 1961-08-15 | Du Pont | End closures |
| US2918003A (en) * | 1957-04-29 | 1959-12-22 | Mine Safety Appliances Co | Deep water cartridge |
| FR1365996A (en) * | 1963-04-02 | 1964-07-10 | Ruggieri Ets | Cartridge especially for explosives |
| US3264992A (en) * | 1964-03-09 | 1966-08-09 | Marlin E Beck | Tamping plug |
| NL6511016A (en) * | 1964-09-12 | 1966-03-14 | ||
| DE1288544B (en) * | 1968-01-31 | 1969-02-06 | Dynamit Nobel Ag | Procedure to increase safety when shooting in coal mining |
| US3477373A (en) * | 1968-04-04 | 1969-11-11 | Us Navy | Underwater demolition package |
| AU462018B2 (en) * | 1970-09-21 | 1975-06-12 | Ici Australia Limited | Improvements in and relating to resilient stemming devices |
| FR2254486A1 (en) * | 1973-12-17 | 1975-07-11 | Kwm Schlichter Et Suss Kg | Closed cell foam bottle stopper - has dense smooth external surface and inner cork granules |
| DE2506865A1 (en) * | 1975-02-18 | 1976-08-26 | Feistel Pyrotech Fab | Sealing-filling residual spaces of cartridges - by introducing synthetic resin into space and foaming a resin to effect sealing-filling |
| FR2307843A1 (en) * | 1975-04-15 | 1976-11-12 | Simflex | Cork substitute compsn. for closing foodstuff containers - comprising polyisoprene styrene butadiene copolymer, fillers, blowing and vulcanising agents |
| DE2629417C2 (en) * | 1975-06-30 | 1983-05-11 | Denka Chemical Corp., 77017 Houston, Tex. | Elastomeric composition made from a polychloroprene sol-gel mixture |
| US4000696A (en) * | 1975-09-05 | 1977-01-04 | Excoa, Inc. | Cartridge for two component field mixed explosive |
| US4091136A (en) * | 1976-05-17 | 1978-05-23 | Shaw Plastics Corporation | Synthetic cork-like material and method of making same |
-
1979
- 1979-11-01 GB GB7937952A patent/GB2040412B/en not_active Expired
- 1979-11-01 EP EP79302408A patent/EP0013473B1/en not_active Expired
- 1979-11-15 AU AU52834/79A patent/AU525543B2/en not_active Ceased
- 1979-11-22 JP JP15076779A patent/JPS5596899A/en active Granted
- 1979-12-14 CA CA000342099A patent/CA1146803A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2040412A (en) | 1980-08-28 |
| JPS6350638B2 (en) | 1988-10-11 |
| AU5283479A (en) | 1980-07-24 |
| AU525543B2 (en) | 1982-11-11 |
| JPS5596899A (en) | 1980-07-23 |
| GB2040412B (en) | 1982-08-04 |
| EP0013473B1 (en) | 1986-12-17 |
| EP0013473A1 (en) | 1980-07-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |