CA1140811A - Primer assembly having a delay cap/sensor element hermetically sealed in a shell unit - Google Patents
Primer assembly having a delay cap/sensor element hermetically sealed in a shell unitInfo
- Publication number
- CA1140811A CA1140811A CA000341463A CA341463A CA1140811A CA 1140811 A CA1140811 A CA 1140811A CA 000341463 A CA000341463 A CA 000341463A CA 341463 A CA341463 A CA 341463A CA 1140811 A CA1140811 A CA 1140811A
- Authority
- CA
- Canada
- Prior art keywords
- assembly
- primer
- cap
- delay
- shell
- 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
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
- F42D1/04—Arrangements for ignition
-
- 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
- F42B3/26—Arrangements for mounting initiators; Accessories therefor, e.g. tools
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
- F42D1/04—Arrangements for ignition
- F42D1/043—Connectors for detonating cords and ignition tubes, e.g. Nonel tubes
Abstract
Abstract Primer Assembly A cast or pressed explosive primer is provided which is adapted for slidable initiating engagement with a deto-nating cord. The primer comprises two hermetically sealed shells or cups which are connected together. One shell con-tains a sensor/signal carrier/delay cap combination and the second shell contains the explosive primer charge. Guides are provided on the outside of the shells for the threading therethrough of a detonating cord, The construction provides protection against the ingress of water or other liquids which may desensitize the initiation system,
Description
11~0811 Primer AssemblY
This invention relates to the initiation of low sensiti-vity explosives in large diameter, vertical boreholes such as in open pit and underground mining and quarrying operations.
In particular, the invention relates to an explosive primer assembly adapted for initiation by means of detonating cord and delay action blasting caps in vertical boreholes charged with a low sensitivity blasting agent.
To achieve the optimum use of explosive energy, to re-duce ground vibrations, and to minimize any detrimental ef-fects to the surrounding environment, it is now well known to employ time-delay blasting techniques. Briefly described, this kind of blasting involves the charging of a borehole or 15 several boreholes with explosives and placing time-delay initiators at intervals along the explosive column. Such initiators may be electric blasting caps or, preferably, de-lay caps initiated by means of a low energy detonating cord.
Generally the use of electric blasting caps is avoided for 20 safety reasons and as a matter of convenience since a large number of electric lead wires are required for each borehole.
~ Where the explo~ive charge employed is of the low sensitivity `~ ~ type, for example, bulk or packaged ammonium nitrate/fuel oil (ANFO) or aqueous slurry mixtures, it is also necessary to 25 employ a primer or booster charge with each delay blasting cap in order to insure detonation of the relatively insensitive explosive.
' ' ' `. ' '' ' ' ~'''' ,' ' ~, ~, I `` " 1'.... ,'.. .
'- .. .~
Generally, the preferred method of charging a large dia-meter, vertical borehole for time-delay blasting purposes com-prises the steps of placing a length of detonating cord as a down line throughout the length of a borehole and, as the bore-hole is charged with bulk or packaged explosives, primer char-ges each containing a non-electric delay cap, are slid down and in contact with the down line so that the fully charged bore-hole may contain several primers decked at intervals along its length. The delay cap in each of the primers is selected so as to provide the most efficient blasting results. Upon initi-ation of the detonating cord down line, the associated caps and primers are initiated in a planned time-delay sequence.
Typical non-electric time delay blasting methods are described, 15 for example, in United States patent ~o. 4,060,033 and United States patent No. 4,133,247.
In large scale quarrying, underground and open pit mining operations such as in iron ore pit mines, it is the common practise for reasons of economy to load a large number of bore-20 holes with explosives over a period of several days or evenweeks and to thereafter initiate nearly simultaneously all the charged boreholes to detonate in non-electric time-delay se-quence. The employment of such mining methods frequently means that the explosive components in the borehole, including the 25 initiating detonating cord lines, and the delay blasting caps and primers, are exposed for long periods of time to condi-tions of moisture or oil or other chemical contamination from the components of bulk explosives sufficient to cause desensitization of one or other of the delay blasting cap 30 components. While methods have been developed to "waterproof"
the explosive charge and the detonating cords, it has not been possible to provide complete insurance against moisture and oil desensitization for the blasting cap particularly at its point of connection to a length of detonating cord. This 35 is a particular problem with the use of cap-initiated sliding primers of the types described in, for example, United States ' ' ~
ii4V811 patent No. 4,060,033 and United States patent No. 4,133,247, since the initiating caps and/or sensors are exposed to the moisture or oil present in the borehole and may become de-sensitized resulting in a detonation failure. There remainsa need, therefore, for a slider primer assembly of the type comprising a cast or pressed priming charge and an associated cord- or shocX tube-initiated, time-delay cap which may be conveniently used in large diameter vertical boreholes and 10 which can withstand the desensitizing effect of moisture or oil and pressure for long periods of time.
The primer assembly of the present invention provides an economic, convenient, non-electric down-the-hole sliding ini-tiating primer device which resists moisture and oil penetra-lS tion for long periods of time. Generally the invention compri-ses a first shell containing a priming explosive charge and a second shell containing a sensor/signal carrier/delay cap as-sembly, the said second shell being hermetically sealed and adapted for connection to said first shell Aligned detona-20 ting cord tunnels, through which are passed a detonating corddownline, are affixed to or comprise an integral part of the outside of the said first and second shells. The sensor/
signal carrier/delay cap assembly sealed within the said second shell is so arranged that the sensor is held in initiating re-25 lationship with the detonating cord downline passed through theadjacent tunnel. A shock wave generated by the detonation of the downline initiates the sensor thereby generating an energy pulse which is in turn transmitted by the signal carrier to initiate the delay cap. The initiation of the cap after a 30 preset time-delay interval causes detonation of the primer explosive charge and, in turn, the adjacent blasting explosive in the borehole.
The invention will be particularly described by reference ` to the attached drawings wherein:
Fig. 1 is a side elevational view of the delay primer assembly of the present invention showing the assembled first -.
114()8il and second shell units;
Fig. 2 is an exploded side elevational view of the assembly of Fig. 1 showing the first and second shell units separated;
Fig, 3 is a perspective cut-away view of the first shell unit showing the inplaced sensor/signal carrier/delay cap assembly;
Fig. 4 is a cross-sectional view of the second shell 10 unit showing the cast or pressed primer charge.
Fig, 5 is a perspective partly cut-away view of an alter-native embodiment of the primer assembly of the invention;
Fig, 6 is a cut-away view of the sensor/signal carrier/
delay element used in the primer of Fig. 5; and Fig. 7 is schematic view of a borehole charged with explosives and the primer assembly of the present invention.
Referring to the figures of the drawings where like numbers are used to designate like parts, in Fig. 1, 1 re-presents the primer assembly of the invention consisting of 20 an upper shell unit 2 and an adjacent interlocked lower shell unit 3. Upper shell unit 2 has on one side and integral therewith a tubular detonating cord tunnel 4. In alignment with tunnel 4 is a similar tunnel 5 on lower shell unit 3.
A detonating cord section 6 is shown passing through tunnels 25 4 and 5. Sufficient clearance is provided in the tunnels to permit the assembly 1 to slide along cord 6, Fig. 2 shows the assembly of Fig. 1 with shell units 2 and 3 separated and disconnected. On the upper surface of lower shell unit 3 is shown a male threaded or lugged skirt 30 portion 7 which is adapted to interlock with a corresponding female threaded or lugged recess 8 within upper shell unit 2 as shown in Fig. 3. A detonator or cap well 9 is shown in-tegral with and projecting downward from upper shell unit 2.
Fig. 3 shows upper shell unit 2 fitted with an assembly 35 comprising a sensor 10, a signal carrier 11 and a delay cap 12. Shell unit 2 comprises a hollow construction of, for ~ . ~
~14V811 example, molded plastic such as polyethylene , polypropyl~ne or PVC having a separate lid portion 13 which lid may be cemented in place with, for example, an epoxy resin after positioning of sensor/signal carrier/cap assembly 10/11/12 within the confines of unit 2. The wall of unit 2 dividing the unit from cord tunnel 4 comprises a thin wall or membrane area 14 against which sensor 10 is held by means of, for example, retainer 15. Sensor 10 may comprise a tubular metal 10 shell containing explosive material such as, for example, lead azide or lead styphanate, which explosive material is sensiti-ve to initiation from the detonation of the detonating cord within tunnel 4. Upon the sympathetic initiation of the explo-sive material in sensor 10, shock and heat from sensor 10 is 15 transmitted via signal carrier 11 to ignite delay blasting cap 12. Signal carrier 11 may be, for example, a length of hollow plastic tubing of say, 45 mm inside diameter or a length of ~ONEL (Reg. TM) energy transmission tube. Upon the ignition and detonation of delay cap 12, the adjacent primer charge as 20 shown in Fig. 4 is detonated.
Fig. 4 shows lower shell unit 3 which may comprise, for example, a hollow construction of molded plastic, for example, polyethylene, polypropylene or PVC. Within shell unit 3 is shown a typical cast primer charge consisting of an inner sen-25 sitive core of an explosive such as pentaerythritol tetra-nitrate (PETN) 16 surrounded by an outer sheath of a less sensitive explosive such as trinitrotoluene (TNT) 17. The inner core of PET~ may be replaced by a blasting cap or de-tonating cord configuration or other sensitive explosives 30 positioned and imbedded in the cast primary explosive (TNT).
Alternatively, the entire primer explosive charge may com-prise an explosive mixture such as, for example, pentolite, a mixture of PETN and TNT or Composition B, a mixture of RDX
and TNT. Inner cord explosive 16 contains a recess 18 adapted 35 to accommodate cap well 9 of upper shell unit 2. Explosives 16 and 17 are cast or pressed into shell unit 3 using techni-. .
ques well known in the art.
The threaded or lugged area on skirt portion 7 of lowershell unit and the corresponding or lugged area in recess 8 5 are so adapted that when the upper and lower shell units are connected, the detonating cord tunnels 4 and 5 are automatic-ally aligned.
Figs, 5 and 6 show an alternative embodiment of the pri-mer assembly of the invention which consists of a hollow shell 10 unit 30 having integral tubular detonating cord tunnels 4 and 5 on one side thereof. Cord 6 is shown passing through tun-nels 4 and 5. Within shell unit 30 is shown a cast primer charge comprising an inner sensitive e~plosive core 16 and a surrounding less sensitive explosive sheath 17. Inner core 15 16 contains a recess 18 adapted to accommodate a sealed sen-sor/signal carrier/cap assembly unit 31. Assembly unit 31 consists of a tube 32 having a closed end 33 and containing a sensor 10, signal carrier 11 and delay cap 12. An integral thin wall or membrane 14 seals off tube 32 and protects the 20 sensor/signal carrier/cap elements against moisture or of chemical contaminant penetration. End 33 of tube 32 is shown closed at its bottom end by means of a tight fitting or ce-mented on cap or plug 35 to produce water-tightness. Alter-natively, tube 32 may be constructed in two halves adapted 25 to be screwed or snapped together to enclose the sensor/
signal carrier/cap element. At the end of tube 32 and in-gral therewith is a short tunnel element 34 corresponding in dimensions to tunnels 4 and 5. Assembly unit 31 is adapted for insertion into recess 18 with tunnels 34 in alignment 30 with tunnels 4 and 5 so that cord 6 may be passed therethrough.
The detonation of cord 6 initiates the explosive material in sensor 10 which transmits shock and heat through carrier 11 to ignite cap 12. Cap 12 in turn initiates primer charges 16 and 17. Because of the in-line relationship of cap 12 35 and sensor 10 in assembly 31, the signal carrier 11 may be eliminated and sensor 10 attached directly to an open end of cap 12 thus simplifying the construction. In this event a slightly elongated cap 12 may be required.
With reference to Fig. 7, illustrated is a typical bore-hole in rock charged in deck-loaded fashion and employing the primer assemblies of Figs. 1 or 5 Shown is a borehole 18 of, for example 30 cm diameter and 15 m depth Extending into borehole 18 is a detonating cord downline 19 attached to the 10 lower end of which is primer assembly 20 having a delay time of, say, 25 milliseconds. A bulk explosive charge such as a slurry blasting agent, is loaded on and above primer assembly 20 and the charge is in turn covered with inert stemming ma-terial 22 A second charge of explosives 23 is loaded above 15 stemming 22 and simultaneous therewith a second primer as-sembly 24 of, say, 50 milliseconds time dealy, is slid down cord 19 to rest within charge 23. Further stemming 25 is placed over charge 23 and a subsequent explosive charge 26 and primer assembly 27 (75 milliseconds time dealy) are loaded 20 in a like manner. A final stemming 28 is placed over charge 26 Downline 19 is initiated by, for example, electric blasting cap 29 and the detonating cord nearly simultaneously initiates the sensor element in each primer assembly The primer as-semblies are in turn initiated in sequence corresponding to 25 their selected time delay intervals, normally but not neces-sarily from the bottom of the borehole (primer 20) upwards to provide a time controlled blast Because the sensitive elements of the primer assembly of the invention are protected from moisture in the borehole and from the liquid ingredients 30 of the explosive charge, borehole 18 may be charged many days before its time of detonation without risk of detonation failure and the hazards and expense caused thereby
This invention relates to the initiation of low sensiti-vity explosives in large diameter, vertical boreholes such as in open pit and underground mining and quarrying operations.
In particular, the invention relates to an explosive primer assembly adapted for initiation by means of detonating cord and delay action blasting caps in vertical boreholes charged with a low sensitivity blasting agent.
To achieve the optimum use of explosive energy, to re-duce ground vibrations, and to minimize any detrimental ef-fects to the surrounding environment, it is now well known to employ time-delay blasting techniques. Briefly described, this kind of blasting involves the charging of a borehole or 15 several boreholes with explosives and placing time-delay initiators at intervals along the explosive column. Such initiators may be electric blasting caps or, preferably, de-lay caps initiated by means of a low energy detonating cord.
Generally the use of electric blasting caps is avoided for 20 safety reasons and as a matter of convenience since a large number of electric lead wires are required for each borehole.
~ Where the explo~ive charge employed is of the low sensitivity `~ ~ type, for example, bulk or packaged ammonium nitrate/fuel oil (ANFO) or aqueous slurry mixtures, it is also necessary to 25 employ a primer or booster charge with each delay blasting cap in order to insure detonation of the relatively insensitive explosive.
' ' ' `. ' '' ' ' ~'''' ,' ' ~, ~, I `` " 1'.... ,'.. .
'- .. .~
Generally, the preferred method of charging a large dia-meter, vertical borehole for time-delay blasting purposes com-prises the steps of placing a length of detonating cord as a down line throughout the length of a borehole and, as the bore-hole is charged with bulk or packaged explosives, primer char-ges each containing a non-electric delay cap, are slid down and in contact with the down line so that the fully charged bore-hole may contain several primers decked at intervals along its length. The delay cap in each of the primers is selected so as to provide the most efficient blasting results. Upon initi-ation of the detonating cord down line, the associated caps and primers are initiated in a planned time-delay sequence.
Typical non-electric time delay blasting methods are described, 15 for example, in United States patent ~o. 4,060,033 and United States patent No. 4,133,247.
In large scale quarrying, underground and open pit mining operations such as in iron ore pit mines, it is the common practise for reasons of economy to load a large number of bore-20 holes with explosives over a period of several days or evenweeks and to thereafter initiate nearly simultaneously all the charged boreholes to detonate in non-electric time-delay se-quence. The employment of such mining methods frequently means that the explosive components in the borehole, including the 25 initiating detonating cord lines, and the delay blasting caps and primers, are exposed for long periods of time to condi-tions of moisture or oil or other chemical contamination from the components of bulk explosives sufficient to cause desensitization of one or other of the delay blasting cap 30 components. While methods have been developed to "waterproof"
the explosive charge and the detonating cords, it has not been possible to provide complete insurance against moisture and oil desensitization for the blasting cap particularly at its point of connection to a length of detonating cord. This 35 is a particular problem with the use of cap-initiated sliding primers of the types described in, for example, United States ' ' ~
ii4V811 patent No. 4,060,033 and United States patent No. 4,133,247, since the initiating caps and/or sensors are exposed to the moisture or oil present in the borehole and may become de-sensitized resulting in a detonation failure. There remainsa need, therefore, for a slider primer assembly of the type comprising a cast or pressed priming charge and an associated cord- or shocX tube-initiated, time-delay cap which may be conveniently used in large diameter vertical boreholes and 10 which can withstand the desensitizing effect of moisture or oil and pressure for long periods of time.
The primer assembly of the present invention provides an economic, convenient, non-electric down-the-hole sliding ini-tiating primer device which resists moisture and oil penetra-lS tion for long periods of time. Generally the invention compri-ses a first shell containing a priming explosive charge and a second shell containing a sensor/signal carrier/delay cap as-sembly, the said second shell being hermetically sealed and adapted for connection to said first shell Aligned detona-20 ting cord tunnels, through which are passed a detonating corddownline, are affixed to or comprise an integral part of the outside of the said first and second shells. The sensor/
signal carrier/delay cap assembly sealed within the said second shell is so arranged that the sensor is held in initiating re-25 lationship with the detonating cord downline passed through theadjacent tunnel. A shock wave generated by the detonation of the downline initiates the sensor thereby generating an energy pulse which is in turn transmitted by the signal carrier to initiate the delay cap. The initiation of the cap after a 30 preset time-delay interval causes detonation of the primer explosive charge and, in turn, the adjacent blasting explosive in the borehole.
The invention will be particularly described by reference ` to the attached drawings wherein:
Fig. 1 is a side elevational view of the delay primer assembly of the present invention showing the assembled first -.
114()8il and second shell units;
Fig. 2 is an exploded side elevational view of the assembly of Fig. 1 showing the first and second shell units separated;
Fig, 3 is a perspective cut-away view of the first shell unit showing the inplaced sensor/signal carrier/delay cap assembly;
Fig. 4 is a cross-sectional view of the second shell 10 unit showing the cast or pressed primer charge.
Fig, 5 is a perspective partly cut-away view of an alter-native embodiment of the primer assembly of the invention;
Fig, 6 is a cut-away view of the sensor/signal carrier/
delay element used in the primer of Fig. 5; and Fig. 7 is schematic view of a borehole charged with explosives and the primer assembly of the present invention.
Referring to the figures of the drawings where like numbers are used to designate like parts, in Fig. 1, 1 re-presents the primer assembly of the invention consisting of 20 an upper shell unit 2 and an adjacent interlocked lower shell unit 3. Upper shell unit 2 has on one side and integral therewith a tubular detonating cord tunnel 4. In alignment with tunnel 4 is a similar tunnel 5 on lower shell unit 3.
A detonating cord section 6 is shown passing through tunnels 25 4 and 5. Sufficient clearance is provided in the tunnels to permit the assembly 1 to slide along cord 6, Fig. 2 shows the assembly of Fig. 1 with shell units 2 and 3 separated and disconnected. On the upper surface of lower shell unit 3 is shown a male threaded or lugged skirt 30 portion 7 which is adapted to interlock with a corresponding female threaded or lugged recess 8 within upper shell unit 2 as shown in Fig. 3. A detonator or cap well 9 is shown in-tegral with and projecting downward from upper shell unit 2.
Fig. 3 shows upper shell unit 2 fitted with an assembly 35 comprising a sensor 10, a signal carrier 11 and a delay cap 12. Shell unit 2 comprises a hollow construction of, for ~ . ~
~14V811 example, molded plastic such as polyethylene , polypropyl~ne or PVC having a separate lid portion 13 which lid may be cemented in place with, for example, an epoxy resin after positioning of sensor/signal carrier/cap assembly 10/11/12 within the confines of unit 2. The wall of unit 2 dividing the unit from cord tunnel 4 comprises a thin wall or membrane area 14 against which sensor 10 is held by means of, for example, retainer 15. Sensor 10 may comprise a tubular metal 10 shell containing explosive material such as, for example, lead azide or lead styphanate, which explosive material is sensiti-ve to initiation from the detonation of the detonating cord within tunnel 4. Upon the sympathetic initiation of the explo-sive material in sensor 10, shock and heat from sensor 10 is 15 transmitted via signal carrier 11 to ignite delay blasting cap 12. Signal carrier 11 may be, for example, a length of hollow plastic tubing of say, 45 mm inside diameter or a length of ~ONEL (Reg. TM) energy transmission tube. Upon the ignition and detonation of delay cap 12, the adjacent primer charge as 20 shown in Fig. 4 is detonated.
Fig. 4 shows lower shell unit 3 which may comprise, for example, a hollow construction of molded plastic, for example, polyethylene, polypropylene or PVC. Within shell unit 3 is shown a typical cast primer charge consisting of an inner sen-25 sitive core of an explosive such as pentaerythritol tetra-nitrate (PETN) 16 surrounded by an outer sheath of a less sensitive explosive such as trinitrotoluene (TNT) 17. The inner core of PET~ may be replaced by a blasting cap or de-tonating cord configuration or other sensitive explosives 30 positioned and imbedded in the cast primary explosive (TNT).
Alternatively, the entire primer explosive charge may com-prise an explosive mixture such as, for example, pentolite, a mixture of PETN and TNT or Composition B, a mixture of RDX
and TNT. Inner cord explosive 16 contains a recess 18 adapted 35 to accommodate cap well 9 of upper shell unit 2. Explosives 16 and 17 are cast or pressed into shell unit 3 using techni-. .
ques well known in the art.
The threaded or lugged area on skirt portion 7 of lowershell unit and the corresponding or lugged area in recess 8 5 are so adapted that when the upper and lower shell units are connected, the detonating cord tunnels 4 and 5 are automatic-ally aligned.
Figs, 5 and 6 show an alternative embodiment of the pri-mer assembly of the invention which consists of a hollow shell 10 unit 30 having integral tubular detonating cord tunnels 4 and 5 on one side thereof. Cord 6 is shown passing through tun-nels 4 and 5. Within shell unit 30 is shown a cast primer charge comprising an inner sensitive e~plosive core 16 and a surrounding less sensitive explosive sheath 17. Inner core 15 16 contains a recess 18 adapted to accommodate a sealed sen-sor/signal carrier/cap assembly unit 31. Assembly unit 31 consists of a tube 32 having a closed end 33 and containing a sensor 10, signal carrier 11 and delay cap 12. An integral thin wall or membrane 14 seals off tube 32 and protects the 20 sensor/signal carrier/cap elements against moisture or of chemical contaminant penetration. End 33 of tube 32 is shown closed at its bottom end by means of a tight fitting or ce-mented on cap or plug 35 to produce water-tightness. Alter-natively, tube 32 may be constructed in two halves adapted 25 to be screwed or snapped together to enclose the sensor/
signal carrier/cap element. At the end of tube 32 and in-gral therewith is a short tunnel element 34 corresponding in dimensions to tunnels 4 and 5. Assembly unit 31 is adapted for insertion into recess 18 with tunnels 34 in alignment 30 with tunnels 4 and 5 so that cord 6 may be passed therethrough.
The detonation of cord 6 initiates the explosive material in sensor 10 which transmits shock and heat through carrier 11 to ignite cap 12. Cap 12 in turn initiates primer charges 16 and 17. Because of the in-line relationship of cap 12 35 and sensor 10 in assembly 31, the signal carrier 11 may be eliminated and sensor 10 attached directly to an open end of cap 12 thus simplifying the construction. In this event a slightly elongated cap 12 may be required.
With reference to Fig. 7, illustrated is a typical bore-hole in rock charged in deck-loaded fashion and employing the primer assemblies of Figs. 1 or 5 Shown is a borehole 18 of, for example 30 cm diameter and 15 m depth Extending into borehole 18 is a detonating cord downline 19 attached to the 10 lower end of which is primer assembly 20 having a delay time of, say, 25 milliseconds. A bulk explosive charge such as a slurry blasting agent, is loaded on and above primer assembly 20 and the charge is in turn covered with inert stemming ma-terial 22 A second charge of explosives 23 is loaded above 15 stemming 22 and simultaneous therewith a second primer as-sembly 24 of, say, 50 milliseconds time dealy, is slid down cord 19 to rest within charge 23. Further stemming 25 is placed over charge 23 and a subsequent explosive charge 26 and primer assembly 27 (75 milliseconds time dealy) are loaded 20 in a like manner. A final stemming 28 is placed over charge 26 Downline 19 is initiated by, for example, electric blasting cap 29 and the detonating cord nearly simultaneously initiates the sensor element in each primer assembly The primer as-semblies are in turn initiated in sequence corresponding to 25 their selected time delay intervals, normally but not neces-sarily from the bottom of the borehole (primer 20) upwards to provide a time controlled blast Because the sensitive elements of the primer assembly of the invention are protected from moisture in the borehole and from the liquid ingredients 30 of the explosive charge, borehole 18 may be charged many days before its time of detonation without risk of detonation failure and the hazards and expense caused thereby
Claims (6)
1. A delay primer assembly comprising a first shell unit containing a primer explosive charge and a second shell unit containing a non-electric delay blasting cap to which is operatively connected a signal carrier and a sensor element, the said delay cap, signal carrier and sensor element being hermetically sealed within the said second shell unit, the first and second shell units being interconnectable in such a manner that initiation of the said second shell unit blast-ing cap causes detonation of said first shell unit primer explosive charge, both said first and second shell units having integrally attached in alignment to their outer walls guide means by which a detonating cord may be brought into slidable initiating contact with the said sensor element
2. An assembly as claimed in Claim 1 wherein the said shell units and integral cord guide means are comprised of a moldable plastic material.
3. An assembly as claimed in Claim 2 wherein the plastic material is selected from polyethylene, polypropylene and polyvinyl chloride.
4. An assembly as claimed in Claim 1 wherein the said primer explosive comprises cast or pressed PETN, TNT or mixtures of these
5. An assembly as claimed in Claim 1 wherein the said detonator cord guide means comprise tubular elements.
6. An assembly as claimed in Claim 1 wherein the said sensor element is directly connected to the said delay cap.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000341463A CA1140811A (en) | 1979-12-07 | 1979-12-07 | Primer assembly having a delay cap/sensor element hermetically sealed in a shell unit |
| US06/205,422 US4383484A (en) | 1979-12-07 | 1980-11-10 | Primer assembly |
| AU64318/80A AU6431880A (en) | 1979-12-07 | 1980-11-12 | Primer assembly |
| ZA00807184A ZA807184B (en) | 1979-12-07 | 1980-11-19 | Primer assembly |
| MX185074A MX156878A (en) | 1979-12-07 | 1980-12-05 | IMPROVEMENTS TO DELAY DETONATOR DEVICE |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000341463A CA1140811A (en) | 1979-12-07 | 1979-12-07 | Primer assembly having a delay cap/sensor element hermetically sealed in a shell unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1140811A true CA1140811A (en) | 1983-02-08 |
Family
ID=4115779
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000341463A Expired CA1140811A (en) | 1979-12-07 | 1979-12-07 | Primer assembly having a delay cap/sensor element hermetically sealed in a shell unit |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4383484A (en) |
| AU (1) | AU6431880A (en) |
| CA (1) | CA1140811A (en) |
| MX (1) | MX156878A (en) |
| ZA (1) | ZA807184B (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4527482A (en) * | 1981-10-23 | 1985-07-09 | Hynes Frederick B W | Blasting cap to primer adapter |
| EP0109161B1 (en) * | 1982-10-14 | 1987-02-04 | Titanite Limited | Blasting-cartridge case |
| US4718345A (en) * | 1984-06-01 | 1988-01-12 | E. I. Du Pont De Nemours And Company | Primer assembly |
| US4796533A (en) * | 1985-03-25 | 1989-01-10 | Eti Explosives Technologies International Inc. | Primer assembly |
| US4637312A (en) * | 1985-05-01 | 1987-01-20 | E. I. Du Pont De Nemours And Company | Explosive primer and carrier therefor |
| GB2200436B (en) * | 1987-01-30 | 1990-04-11 | Ici Australia Operations | Primer |
| US4799428A (en) * | 1987-04-06 | 1989-01-24 | Explosives Technologies International Inc. | Explosive primer unit for instantaneous initiation by low-energy detonating cord |
| US4776276A (en) * | 1987-05-06 | 1988-10-11 | Eti Explosives Technologies International Inc. | Cast explosive primer initiatable by low-energy detonating cord |
| US5005641A (en) * | 1990-07-02 | 1991-04-09 | Mohaupt Henry H | Gas generator with improved ignition assembly |
| US5435250A (en) * | 1992-09-25 | 1995-07-25 | Pollock; Edward S. | Explosive packaging system |
| US5780764A (en) * | 1996-01-11 | 1998-07-14 | The Ensign-Bickford Company | Booster explosive devices and combinations thereof with explosive accessory charges |
| US5614693A (en) * | 1996-01-11 | 1997-03-25 | The Ensign-Bickford Company | Accessory charges for booster explosive devices |
| US5661256A (en) * | 1996-01-16 | 1997-08-26 | The Ensign-Bickford Company | Slider member for booster explosive charges |
| US5763816A (en) * | 1996-07-26 | 1998-06-09 | Slurry Explosive Corporation | Explosive primer |
| US6186069B1 (en) * | 1998-04-09 | 2001-02-13 | Ensign-Bickford (South Africa Proprietary) Limited | Explosives booster |
| US6295912B1 (en) * | 1999-05-20 | 2001-10-02 | Halliburton Energy Services, Inc. | Positive alignment insert (PAI) with imbedded explosive |
| US8127682B1 (en) * | 2006-02-01 | 2012-03-06 | John Sonday | Cast booster using novel explosive core |
| US7823508B2 (en) * | 2006-08-24 | 2010-11-02 | Orica Explosives Technology Pty Ltd | Connector for detonator, corresponding booster assembly, and method of use |
| US8333854B2 (en) * | 2007-04-18 | 2012-12-18 | University Of Central Florida Research Foundation, Inc. | Thermite compositions, articles and low temperature impact milling processes for forming the same |
| US8256337B2 (en) * | 2008-03-07 | 2012-09-04 | Baker Hughes Incorporated | Modular initiator |
| DE102009012632A1 (en) * | 2009-03-10 | 2010-09-23 | Fresenius Medical Care Deutschland Gmbh | A sealing device for sealing a volume of a medical treatment arrangement against another volume and arrangement and method |
| AU2012253612B2 (en) | 2011-05-10 | 2015-10-29 | Dyno Nobel Inc. | Canisters with integral locking means and cast booster explosives comprising the same |
| CA2953686A1 (en) | 2014-07-02 | 2016-01-07 | Orica International Pte Ltd | A shell for use in blasting |
| MX2022010045A (en) | 2020-02-19 | 2022-10-10 | Dyno Nobel Inc | Canister assembly with protected cap well and booster explosive comprising the same. |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3058419A (en) * | 1959-07-16 | 1962-10-16 | Atlas Chem Ind | Blasting assembly |
| US3141410A (en) * | 1962-02-08 | 1964-07-21 | Chromalloy Corp | Blasting initiator |
| US3183836A (en) * | 1963-08-21 | 1965-05-18 | Trojan Powder Co | Canister for cast primer |
| US3604353A (en) * | 1968-12-24 | 1971-09-14 | Hercules Inc | Cast booster assembly |
| CA934224A (en) * | 1971-02-17 | 1973-09-25 | Towell Gordon | Primer cartridge |
| US3831522A (en) * | 1973-03-02 | 1974-08-27 | R Romney | Explosive booster and container therefor |
| US4023494A (en) * | 1975-11-03 | 1977-05-17 | Tyler Holding Company | Explosive container |
| US4060034A (en) * | 1976-03-09 | 1977-11-29 | Atlas Powder Company | Delay booster assembly |
| US4165691A (en) * | 1977-08-29 | 1979-08-28 | Atlas Powder Company | Delay detonator and its use with explosive packaged boosters and cartridges |
| US4178852A (en) * | 1977-08-29 | 1979-12-18 | Atlas Powder Company | Delay actuated explosive device |
| US4295424A (en) * | 1979-04-24 | 1981-10-20 | Atlas Powder Company | Explosive container for cast primer |
-
1979
- 1979-12-07 CA CA000341463A patent/CA1140811A/en not_active Expired
-
1980
- 1980-11-10 US US06/205,422 patent/US4383484A/en not_active Expired - Lifetime
- 1980-11-12 AU AU64318/80A patent/AU6431880A/en not_active Abandoned
- 1980-11-19 ZA ZA00807184A patent/ZA807184B/en unknown
- 1980-12-05 MX MX185074A patent/MX156878A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| US4383484A (en) | 1983-05-17 |
| MX156878A (en) | 1988-10-10 |
| AU6431880A (en) | 1981-06-11 |
| ZA807184B (en) | 1981-11-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |