WO2007110819A1 - Detonation of explosives - Google Patents
Detonation of explosives Download PDFInfo
- Publication number
- WO2007110819A1 WO2007110819A1 PCT/IB2007/051008 IB2007051008W WO2007110819A1 WO 2007110819 A1 WO2007110819 A1 WO 2007110819A1 IB 2007051008 W IB2007051008 W IB 2007051008W WO 2007110819 A1 WO2007110819 A1 WO 2007110819A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- charge
- casing
- sealing
- timer
- time delay
- Prior art date
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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
- F42B3/10—Initiators therefor
- F42B3/16—Pyrotechnic delay initiators
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
- C06C7/00—Non-electric detonators; Blasting caps; Primers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
- F42C9/00—Time fuzes; Combined time and percussion or pressure-actuated fuzes; Fuzes for timed self-destruction of ammunition
- F42C9/10—Time fuzes; Combined time and percussion or pressure-actuated fuzes; Fuzes for timed self-destruction of ammunition the timing being caused by combustion
Definitions
- THIS INVENTION relates, broadly, to the detonation of explosives.
- the invention relates to a time delay element for use in a chemical detonator, and to such detonator incorporating the time delay element.
- a time delay element for use in a chemical detonator, the time delay element including, in a tubular casing having open ends, an assembly made up of: a sealing charge made of pyrotechnic material, the sealing charge being in sealing contact with the inner surface of the tubular casing; a timer charge, made of a timing composition and being in contact with the sealing charge; a priming charge in contact with the timing charge and spaced thereby from the sealing charge; and, a base charge, in contact with the priming charge and spaced thereby from the timer charge.
- Such priming charges are also known as primer charges or primary charges.
- the assembly may occupy substantially the whole of the interior of the tubular casing, which is straight.
- the time delay element assembly is for insertion, typically with a sliding fit, into a deep, cup-shaped housing to form a chemical detonator, the pyrotechnic material of the sealing charge being ignitable, preferably easily by a member of the group consisting of a shock tube and electrical matchheads, at a position remote from the timer charge, the base charge being located at an end of the casing.
- the tubular casing may be constructed from a material selected from the group consisting of ceramics materials, plastics materials and metals. It is expected that it will usually be of a metal selected from the group consisting of aluminium, zinc and aluminium alloys.
- the tubular casing may have a narrowed end and the sealing charge being located between the timer charge and the narrowed end of the casing, the narrowed end being in contact with the sealing charge and acting to hold the sealing charge in place in contact with the timer charge.
- the narrowed end of the casing may form a neck.
- the casing may have an interior passage which is of a cross-section which expands from the narrowed end of the casing into a length of said passage which is of constant cross-section, the length of constant cross-section extending from said narrowed end to the opposite end of the passage and containing a major part of the sealing charge, the timer charge, the priming charge and the base charge, a minor part of the sealing charge being contained in the neck.
- the casing may have an interior passage which is of a cross- section which expands from the narrowed end of the casing into a length of said passage which is of constant cross-section, the length of constant cross-section extending from said narrowed end to an enlarged portion of the passage having a greater cross-section than said length and opening out of the opposite end of the casing, said length containing a major part of the sealing charge, the timer charge and the priming charge, and the enlarged portion containing the base charge.
- the invention extends to a chemical detonator including a housing containing, in its interior, a time delay element as defined and described above.
- the housing may have a depth which is at least five times its diameter.
- An end of the tubular casing may abut the floor of the cup of the housing, the base charge being located between the floor of the cup and the priming charge.
- An end of the tubular casing may be spaced from the floor of the cup of the housing by a base charge located in the housing, between the floor of its cup and the casing, the base charge of the assembly being located in said end of the casing, facing the base charge which spaces the end of the casing from the floor of the cup.
- the housing will be a deep-drawn aluminium cup having a closed end provided by its floor and an open end which receives an initiator selected from the group consisting of shock tubes and electrical matchheads, the housing holding the initiator in initiating relationship with the sealing charge of pyrotechnic material, to permit initiation of the sealing charge by means of the initiator.
- the closed end of the housing may be provided with a cup-shaped connector in which it is held with a friction fit, for connecting the detonator to one or more shock tubes.
- the various charges can, during manufacture of the time delay element, be loaded into the tubular casing in any desired sequence. However, it is expected that it will be desirable to load the timer charge first, to ensure that there is no contamination thereof between its ends by the material of any other charge loaded beforehand, which can affect its burning rate and timing reliability. In this case, the sealing charge of pyrotechnic material will usually be loaded next, followed by the crimping or other narrowing of the tubular casing into the neck over the sealing charge, followed in turn respectively by loading of the priming charge and by the loading of the base charge or part thereof.
- the invention extends accordingly to a method of making a time-delay element for use in a chemical detonator, the method including loading the timer charge, the sealing charge, the priming charge and the base charge in the tubular casing, the charges being loaded into the casing to form a series with the sealing charge at one end of the series, the sealing charge being in contact with the timing charge, the timing charge being in contact with the priming charge, and the priming charge being in contact with the base charge which is at the opposite end of the series.
- the timer charge is loaded first through an end of the casing and is loaded into contact with a plunger which has been inserted into the end of the casing opposite the end of the casing through which the timer charge is loaded.
- Loading of the timer charge may be followed by loading of the sealing charge, which is followed in turn by loading of the priming charge and then by loading of the base charge, the charges being loaded so that the series occupies substantially the whole of the interior of the tubular casing, with the sealing charge and base charge at opposite ends of the casing, the sealing charge being loaded, with the plunger in place, through the same end of the casing as the timer charge and the priming charge and the base charge, after withdrawal of the plunger from the casing, being loaded through the opposite end of the casing.
- the casing may be straight and upright during the loading, the charges being loaded vertically into the casing.
- the timer charge and sealing charge may be loaded downwardly into the casing and, after loading of the timer charge and the sealing charge, the casing being inverted, the priming charge and the base charge being loaded downwardly into the casing, the end of the casing through which the timer charge and sealing charge are loaded being narrowed by crimping it inwardly, after loading of the sealing charge and before loading of the priming charge, to hold the timer charge and the sealing charge in the casing during loading of the priming charge and during loading of the base charge.
- Figure 1 shows a schematic sectional side elevation of a time delay element in accordance with the present invention
- Figure 2 shows a schematic sectional side elevation of a surface chemical detonator according to the invention, employing the time delay element of Figure 1 ;
- Figure 3 shows a schematic sectional side elevation of a variation of the surface detonator of Figure 2
- Figure 4 shows a schematic sectional side elevation of another variation of the surface detonator of Figure 2;
- Figure 5 shows a series of time delay elements of the type shown in Figure 4 and in accordance with the present invention, at various stages during the manufacture thereof; and Figure 6 shows a schematic sectional side elevation of a down-hole detonator in accordance with the invention.
- reference numeral 10 generally designates a time delay element, in accordance with the present invention, for use in a chemical detonator.
- the delay element 10 is of composite construction and comprises an assembly of charges, in a straight tubular aluminium casing 12, of various charges as described hereunder.
- the casing 12 is of generally hollow right-cylindrical shape, having a passage in the shape of a right cylindrical tubular bore 14 in its interior.
- the casing has a neck provided by a crimped or inwardly swaged narrowed end 16 where the passage 14 is narrowed to an opening at 18, and the opposite end of the passage has a diametrically enlarged portion as at 20.
- the passage 18 is of constant cross-section between the narrowed end of the casing and the enlarged portion at 20, the narrowed end expanding into the length of passage of constant cross-section and the length of constant cross-section opening into the portion 20 having a greater cross-section than said length.
- the length of constant cross-section contains a major part of the sealing charge, the remainder of which is contained in the neck 16.
- the casing 12 contains, at its crimped end 16 and held in place thereby, a sealing charge 22 of pyrotechnic material ignitable by a shock tube or electrically by an electrical match head (fuse head), the pyrotechnic material being a composition comprising red lead and silicon.
- a sealing charge 22 is in sealing contact with the interior surface of the base 14 adjacent the crimped end 16 of the casing 12, and is held thereby in abutment with a timer charge 24, made of a timing composition, namely a composition comprising red lead, silicon and barium nitrate.
- a timing composition namely a composition comprising red lead, silicon and barium nitrate.
- suitable pyrotechnic compositions can naturally be used instead.
- the opposite end of the timer charge 24 is in abutment with a priming charge 26 of lead azide (other suitable primary explosives can be used instead) and the opposite end of the priming charge 26, which extends up to the enlarged part 20 of the bore 14, is in contact with a base charge 28 of penta-erythritol tetranitrate located in the enlarged part 20.
- the charges 22, 24, 26 and 28 make up said assembly, the assembly occupying the whole of the interior of the casing, the charge 28 being located in the end of the casing opposite its narrowed end 16.
- FIG 2 the time delay element 10 of Figure 1 is shown located with an interference fit which provides a seal in a housing 30 to provide a detonator, generally designated 32.
- the housing 30 is a cup-shaped deep-drawn aluminium shell having a closed end at 34 against which the base charge 28 abuts, and having a depth more than five times its diameter.
- a rubber sleeve 36 surrounds the crimped end (16 in Figure 1 ) of the casing 12, abutting a shoulder 38 ( Figure 1 ) which is defined at the axially inner extremity of the crimped end and which faces axially outwardly, the sleeve 36 protruding from the open end 40 of the housing 30.
- electrical initiators such as electrical match heads or electrical fuse heads can be used instead.
- Figure 3 retains the same construction as that shown in Figure 2, but it also comprises a cup-shaped connector 46 of moulded plastics construction, its plastics material being polyethylene (in other examples other injection-mouldable materials such as polypropylene can be used instead).
- the open end of the housing 30 is shown having its open end 40 crimped.
- the closed end 34 (see Figure 2) of the housing 30 is inserted into the cup of the connector 46 to abut the closed end of the cup, the casing being held in place in the connector 46 with a friction fit.
- the connector 46 is provided with a resiliently flexible clipping mechanism, in the form of a transverse limb 48, spaced axially outwardly of and connected at one end thereof to the closed end 50 of the connector 46, for clipping up to three acceptor shock tubes (not shown) in place adjacent the base charge 28, where they can have detonations initiated therein by detonation of the base charge 28. In other examples provision can be made for clipping more than three shock tubes in place.
- the limb 48 is spaced from said closed end 50 by a space 52 for receiving the acceptor tubes.
- FIG. 5 a series of delay elements 10 of the type shown in Figure 4 is shown, the series starting at the left-hand side of Figure 5 with the aluminium casing 12 after it has had its shoulder 38 ( Figure 1 ) formed and has been given a taper at 56 at its upper end.
- a plunger (not shown) is inserted from below into its end opposite the taper 56, and part of the timer charge 24 is loaded vertically downwardly from above therein, as shown in the second element of the series.
- Two further parts of the timer charge 24 are loaded in the casing 12 from above, as shown in the third and fourth elements of the series, the full timer charge, after loading, being axially compacted, compressed and consolidated, as shown in the fifth element of the series.
- the sealing charge 22 is then loaded in place from above (the sixth element of the series), and the tapered end 56 is then crimped at 16 over the sealing charge 22 (the seventh element of the series), to seal the sealing charge 22 to the inner surface of the casing 12 and to hold the charges 22 and 24 in place.
- the casing 12 is then inverted (the eighth element in the series) and the primer or primary charge 26 and is then loaded from above into the casing 12.
- the part 28.1 of the base charge is loaded from above into the casing 12 to provide the element 10 (the ninth element of the series), and to ensure that the sealing charge 22 seals against the casing 12 in the crimped end 16.
- the element 10 is now complete and is ready for insertion into the open end 40 of the housing 30, after the major part 28.2 of the base charge 28 has been loaded into the casing 30 against its closed end 34, with the parts 28.1 and 28.2 of the base charge in abutment.
- the crimping of the casing 12 can be the first step, followed, via the opposite end of the casing 12, by loading in turn of the sealing charge 22, the timer charge 24, the primary charge 26 and the part 28.1 of the base charge.
- an advantage of the invention is that the element 10 can be mass-produced by way of an automated process.
- Each element 10, whether of the type shown in Figure 1 and 2, or of the type shown in Figures 4, 5 and 6, can be used in detonators of different strengths, simply by altering the depth of the housing 30, and employing base charges 28.2 which are of different sizes.
- the element 10 of Figures 1 and 2 can be used by itself, with the whole of the base charge 28, 28.1 located in the passage 14, or with the base charge 28, 28.1 in the passage 14 used together with a base charge 28.2 located in the housing 30, between the element 10 and the closed end 34 of the housing 30, in the fashion shown in Figures 4 and 6.
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Abstract
This invention relates to a time delay element, for use in a chemical detonator, the time delay element including an assembly, in a tubular casing having open ends, of : a timer charge made of a timing composition; a sealing charge made of a pyrotechnic material at one end of the timer charge, in contact therewith and in sealing contact with the inner surface of the tubular casing; a priming charge in contact with the end of the timing charge opposite the sealing charge; and at least part of a base charge being in contact with the end of the priming charge opposite the timer charge. The invention also extends to a chemical detonator including such a time delay element, and it extends, further still, to a method of manufacturing such time delay elements.
Description
DETONATION OF EXPLOSIVES
THIS INVENTION relates, broadly, to the detonation of explosives.
More particularly, the invention relates to a time delay element for use in a chemical detonator, and to such detonator incorporating the time delay element.
According to the invention there is provided a time delay element, for use in a chemical detonator, the time delay element including, in a tubular casing having open ends, an assembly made up of: a sealing charge made of pyrotechnic material, the sealing charge being in sealing contact with the inner surface of the tubular casing; a timer charge, made of a timing composition and being in contact with the sealing charge; a priming charge in contact with the timing charge and spaced thereby from the sealing charge; and, a base charge, in contact with the priming charge and spaced thereby from the timer charge.
Such priming charges are also known as primer charges or primary charges.
The assembly may occupy substantially the whole of the interior of the tubular casing, which is straight. The time delay element assembly is for insertion,
typically with a sliding fit, into a deep, cup-shaped housing to form a chemical detonator, the pyrotechnic material of the sealing charge being ignitable, preferably easily by a member of the group consisting of a shock tube and electrical matchheads, at a position remote from the timer charge, the base charge being located at an end of the casing.
The tubular casing may be constructed from a material selected from the group consisting of ceramics materials, plastics materials and metals. It is expected that it will usually be of a metal selected from the group consisting of aluminium, zinc and aluminium alloys. The tubular casing may have a narrowed end and the sealing charge being located between the timer charge and the narrowed end of the casing, the narrowed end being in contact with the sealing charge and acting to hold the sealing charge in place in contact with the timer charge. In the case of an aluminium casing, the narrowed end of the casing may form a neck.
The casing may have an interior passage which is of a cross-section which expands from the narrowed end of the casing into a length of said passage which is of constant cross-section, the length of constant cross-section extending from said narrowed end to the opposite end of the passage and containing a major part of the sealing charge, the timer charge, the priming charge and the base charge, a minor part of the sealing charge being contained in the neck.
Instead, the casing may have an interior passage which is of a cross- section which expands from the narrowed end of the casing into a length of said passage which is of constant cross-section, the length of constant cross-section
extending from said narrowed end to an enlarged portion of the passage having a greater cross-section than said length and opening out of the opposite end of the casing, said length containing a major part of the sealing charge, the timer charge and the priming charge, and the enlarged portion containing the base charge.
The invention extends to a chemical detonator including a housing containing, in its interior, a time delay element as defined and described above.
The housing may have a depth which is at least five times its diameter. An end of the tubular casing may abut the floor of the cup of the housing, the base charge being located between the floor of the cup and the priming charge.
An end of the tubular casing may be spaced from the floor of the cup of the housing by a base charge located in the housing, between the floor of its cup and the casing, the base charge of the assembly being located in said end of the casing, facing the base charge which spaces the end of the casing from the floor of the cup. Typically, the housing will be a deep-drawn aluminium cup having a closed end provided by its floor and an open end which receives an initiator selected from the group consisting of shock tubes and electrical matchheads, the housing holding the initiator in initiating relationship with the sealing charge of pyrotechnic material, to permit initiation of the sealing charge by means of the initiator. The closed end of the housing may be provided with a cup-shaped connector in which it is held with a friction fit, for connecting the detonator to one or more shock tubes.
The various charges can, during manufacture of the time delay element, be loaded into the tubular casing in any desired sequence. However, it is expected that it will be desirable to load the timer charge first, to ensure that there is no contamination thereof between its ends by the material of any other charge loaded beforehand, which can affect its burning rate and timing reliability. In this case, the sealing charge of pyrotechnic material will usually be loaded next, followed by the crimping or other narrowing of the tubular casing into the neck over the sealing charge, followed in turn respectively by loading of the priming charge and by the loading of the base charge or part thereof.
The invention extends accordingly to a method of making a time-delay element for use in a chemical detonator, the method including loading the timer charge, the sealing charge, the priming charge and the base charge in the tubular casing, the charges being loaded into the casing to form a series with the sealing charge at one end of the series, the sealing charge being in contact with the timing charge, the timing charge being in contact with the priming charge, and the priming charge being in contact with the base charge which is at the opposite end of the series.
Preferably, the timer charge is loaded first through an end of the casing and is loaded into contact with a plunger which has been inserted into the end of the casing opposite the end of the casing through which the timer charge is loaded.
Loading of the timer charge may be followed by loading of the sealing charge, which is followed in turn by loading of the priming charge and then by loading
of the base charge, the charges being loaded so that the series occupies substantially the whole of the interior of the tubular casing, with the sealing charge and base charge at opposite ends of the casing, the sealing charge being loaded, with the plunger in place, through the same end of the casing as the timer charge and the priming charge and the base charge, after withdrawal of the plunger from the casing, being loaded through the opposite end of the casing.
The casing may be straight and upright during the loading, the charges being loaded vertically into the casing.
The timer charge and sealing charge may be loaded downwardly into the casing and, after loading of the timer charge and the sealing charge, the casing being inverted, the priming charge and the base charge being loaded downwardly into the casing, the end of the casing through which the timer charge and sealing charge are loaded being narrowed by crimping it inwardly, after loading of the sealing charge and before loading of the priming charge, to hold the timer charge and the sealing charge in the casing during loading of the priming charge and during loading of the base charge.
The invention will now be described, by way of non-limiting illustrative example, with the reference to the accompanying diagrammatic drawings, in which:
Figure 1 shows a schematic sectional side elevation of a time delay element in accordance with the present invention;
Figure 2 shows a schematic sectional side elevation of a surface chemical detonator according to the invention, employing the time delay element of Figure 1 ;
Figure 3 shows a schematic sectional side elevation of a variation of the surface detonator of Figure 2; Figure 4 shows a schematic sectional side elevation of another variation of the surface detonator of Figure 2;
Figure 5 shows a series of time delay elements of the type shown in Figure 4 and in accordance with the present invention, at various stages during the manufacture thereof; and Figure 6 shows a schematic sectional side elevation of a down-hole detonator in accordance with the invention.
In Figure 1 of the drawings, reference numeral 10 generally designates a time delay element, in accordance with the present invention, for use in a chemical detonator. The delay element 10 is of composite construction and comprises an assembly of charges, in a straight tubular aluminium casing 12, of various charges as described hereunder. The casing 12 is of generally hollow right-cylindrical shape, having a passage in the shape of a right cylindrical tubular bore 14 in its interior. The casing has a neck provided by a crimped or inwardly swaged narrowed end 16 where the passage 14 is narrowed to an opening at 18, and the opposite end of the passage has a diametrically enlarged portion as at 20. The passage 18 is of constant cross-section between the narrowed end of the casing and the enlarged portion at 20, the narrowed end expanding into the length of passage of constant cross-section and the length of constant cross-section opening into the portion 20 having a greater cross-section than said length. The length of constant cross-section
contains a major part of the sealing charge, the remainder of which is contained in the neck 16.
In accordance with the invention the casing 12 contains, at its crimped end 16 and held in place thereby, a sealing charge 22 of pyrotechnic material ignitable by a shock tube or electrically by an electrical match head (fuse head), the pyrotechnic material being a composition comprising red lead and silicon. In other examples other suitable pyrotechnic compositions can naturally be used instead. The sealing charge 22 is in sealing contact with the interior surface of the base 14 adjacent the crimped end 16 of the casing 12, and is held thereby in abutment with a timer charge 24, made of a timing composition, namely a composition comprising red lead, silicon and barium nitrate. In other examples other suitable pyrotechnic compositions can naturally be used instead. The opposite end of the timer charge 24 is in abutment with a priming charge 26 of lead azide (other suitable primary explosives can be used instead) and the opposite end of the priming charge 26, which extends up to the enlarged part 20 of the bore 14, is in contact with a base charge 28 of penta-erythritol tetranitrate located in the enlarged part 20. The charges 22, 24, 26 and 28 make up said assembly, the assembly occupying the whole of the interior of the casing, the charge 28 being located in the end of the casing opposite its narrowed end 16.
In Figure 2 the time delay element 10 of Figure 1 is shown located with an interference fit which provides a seal in a housing 30 to provide a detonator, generally designated 32. The housing 30 is a cup-shaped deep-drawn aluminium shell having a closed end at 34 against which the base charge 28 abuts, and having
a depth more than five times its diameter. A rubber sleeve 36 surrounds the crimped end (16 in Figure 1 ) of the casing 12, abutting a shoulder 38 (Figure 1 ) which is defined at the axially inner extremity of the crimped end and which faces axially outwardly, the sleeve 36 protruding from the open end 40 of the housing 30. The housing 30, at its open end 40, is crimped inwardly against the sleeve 36 to hold the sleeve in position against an initiator in the form of a shock tube 42 inserted into the open end 40 of the housing 30, with the inserted end 44 of the shock tube 42 spaced from the opening 18 in the crimped end 16 of the casing 12. The end of the casing 12 containing the base charge 28 abuts the floor of the cup of the housing 30, opposite its open end 40. In other examples electrical initiators such as electrical match heads or electrical fuse heads can be used instead.
In Figure 3 the same reference numerals are used to designate the same parts as in Figure 2, unless otherwise stated. Figure 3 retains the same construction as that shown in Figure 2, but it also comprises a cup-shaped connector 46 of moulded plastics construction, its plastics material being polyethylene (in other examples other injection-mouldable materials such as polypropylene can be used instead). The open end of the housing 30 is shown having its open end 40 crimped. The closed end 34 (see Figure 2) of the housing 30 is inserted into the cup of the connector 46 to abut the closed end of the cup, the casing being held in place in the connector 46 with a friction fit. The connector 46 is provided with a resiliently flexible clipping mechanism, in the form of a transverse limb 48, spaced axially outwardly of and connected at one end thereof to the closed end 50 of the connector 46, for clipping up to three acceptor shock tubes (not shown) in place adjacent the base charge 28, where they can have detonations initiated therein by detonation of the
base charge 28. In other examples provision can be made for clipping more than three shock tubes in place. The limb 48 is spaced from said closed end 50 by a space 52 for receiving the acceptor tubes.
Turning to Figure 4, the same reference numerals are used as in Figure
3, unless otherwise stated, the connector 46 of Figure 3 being omitted from Figure 4. The essential difference between the detonator 32 of Figure 4 and that of Figure 3 is that, while the detonator 32 of Figure 3 uses the element 10 of Figure 1 in which the whole base charge 28 is located in the enlarged portion 20 of the passage 14, in Figure 4 the base charge 28.1 is located at the end of the length of passage 14 of constant cross-section, there being no enlarged portion 20, the base charge 28.1 in the passage 14 being of the same diameter as the charges 22, 24 and 26, i.e. the same as that of the passage 14. A further base charge 28.2 is located in the housing 30, against the closed end 34 thereof, between the element 10 and said closed end 34, in abutment with the base charge 28.1 . The open end 40 of the casing 30 has again been crimped.
Turning to Figure 5, a series of delay elements 10 of the type shown in Figure 4 is shown, the series starting at the left-hand side of Figure 5 with the aluminium casing 12 after it has had its shoulder 38 (Figure 1 ) formed and has been given a taper at 56 at its upper end. A plunger (not shown) is inserted from below into its end opposite the taper 56, and part of the timer charge 24 is loaded vertically downwardly from above therein, as shown in the second element of the series. Two further parts of the timer charge 24 are loaded in the casing 12 from above, as shown in the third and fourth elements of the series, the full timer charge, after loading,
being axially compacted, compressed and consolidated, as shown in the fifth element of the series. The sealing charge 22 is then loaded in place from above (the sixth element of the series), and the tapered end 56 is then crimped at 16 over the sealing charge 22 (the seventh element of the series), to seal the sealing charge 22 to the inner surface of the casing 12 and to hold the charges 22 and 24 in place. The casing 12 is then inverted (the eighth element in the series) and the primer or primary charge 26 and is then loaded from above into the casing 12. Finally, the part 28.1 of the base charge is loaded from above into the casing 12 to provide the element 10 (the ninth element of the series), and to ensure that the sealing charge 22 seals against the casing 12 in the crimped end 16. The element 10 is now complete and is ready for insertion into the open end 40 of the housing 30, after the major part 28.2 of the base charge 28 has been loaded into the casing 30 against its closed end 34, with the parts 28.1 and 28.2 of the base charge in abutment.
Naturally, other examples of ways of making the delay elements 10 exist, different from that described with reference to Figure 5. Thus, in one case the crimping of the casing 12 (see the 7th element in the series of Figure 5) can be the first step, followed, via the opposite end of the casing 12, by loading in turn of the sealing charge 22, the timer charge 24, the primary charge 26 and the part 28.1 of the base charge.
Finally, in Figure 6 a down-hole detonator 32 is shown, and the same parts are given the same reference numerals as in Figure 4, unless otherwise stated. The essential difference between the detonator 32 of Figure 6 and that of Figure 4, is
that the base charge 28.2 in Figure 6 is substantially longer and larger than the base charge 28.2 of Figure 4.
An advantage of the invention, particularly as illustrated in the drawings, is that the element 10 can be mass-produced by way of an automated process. Each element 10, whether of the type shown in Figure 1 and 2, or of the type shown in Figures 4, 5 and 6, can be used in detonators of different strengths, simply by altering the depth of the housing 30, and employing base charges 28.2 which are of different sizes. It will be appreciated that the element 10 of Figures 1 and 2 can be used by itself, with the whole of the base charge 28, 28.1 located in the passage 14, or with the base charge 28, 28.1 in the passage 14 used together with a base charge 28.2 located in the housing 30, between the element 10 and the closed end 34 of the housing 30, in the fashion shown in Figures 4 and 6.
Claims
1 . A time delay element, for use in a chemical detonator, the time delay element including, in a tubular casing having open ends, an assembly made up of: a sealing charge made of a pyrotechnic material, the sealing charge being in sealing contact with the inner surface of the tubular casing; a timer charge, made of a timing composition, and being in contact with the sealing charge; a priming charge in contact with the timing charge and spaced thereby from the sealing charge; and a base charge, in contact with the priming charge and spaced thereby from the timer charge.
2. A time delay element according to claim 1 wherein the assembly occupies substantially the whole of the interior of the tubular casing, which is straight.
3. A time delay element according to claim 1 or claim 2 wherein the pyrotechnic material of the sealing charge is ignitable by a member of the group consisting of shock tubes and electrical match heads, at a position remote from the timer charge, the base charge being located at an end of the casing.
4. A time delay element according to any one of claims 1 -3 wherein the tubular casing is constructed from a material selected from the group consisting of ceramics materials, plastics materials and metals.
5. A time delay element according to claim 4 wherein the casing is constructed from a metal selected from the group consisting of aluminium, zinc, and aluminium alloys.
6. A time delay element according to any preceding claim wherein the tubular casing has a narrowed end and wherein the sealing charge is located between the timer charge and the narrowed end of the casing, the narrowed end being in contact with the sealing charge and acting to hold the sealing charge in place in contact with the timer charge.
7. A time delay element according to claim 6 wherein the casing is constructed from aluminium and wherein the narrowed end of the casing forms a neck.
8. A time delay element according to claim 6 or claim 7 wherein the casing has an interior passage which is of a cross-section which expands from the narrowed end of the casing into a length of said passage which is of constant cross-section, the length of constant cross-section extending from said narrowed end to the opposite end of the passage and containing a major part of the sealing charge, the timer charge, the priming charge and the base charge.
9. A time delay element according to claim 6 or claim 7 wherein the casing has an interior passage which is of a cross-section which expands from the narrowed end of the casing into a length of said passage which is of constant cross-section, the length of constant cross-section extending from said narrowed end to an enlarged portion of the passage having a greater cross-section than said length and opening out of the opposite end of the casing, said length containing a major part of the sealing charge, the timer charge and the priming charge, and the enlarged portion containing the base charge.
10. A chemical detonator including a housing containing, in its interior, a time delay element according to any one of claims 1 - 9.
1 1 . A chemical detonator according to claim 10 wherein the housing is cup- shaped, the housing having a depth which is at least five times its diameter.
12. A chemical detonator according to claim 9 or claim 10 wherein an end of the tubular casing abuts the floor of the cup of the housing, the base charge being located between the floor of the cup and the priming charge.
13. A chemical detonator according to claim 1 1 wherein an end of the tubular casing is spaced from the floor of the cup of the housing by a base charge located in the housing, between the floor of its cup and the casing, the base charge of the assembly being located in said end of the casing, facing the base charge which spaces the end of the casing from the floor of the cup.
14. A chemical detonator according to any one of claims 1 1 - 13 wherein the housing is a deep-drawn aluminium cup having a closed end provided by its floor and an open end which receives an initiator selected from the group consisting of shock tubes and electrical match heads, the housing holding the initiator in initiating relationship with the sealing charge of pyrotechnic material, to permit initiation of the sealing charge by means of the initiator.
15. A detonator according to any one of claims 10 - 14 wherein the closed end of the housing is provided with a cup-shaped connector in which it is held with a friction fit, for connecting the detonator to one or more shock tubes.
16. A method of making a time delay element for use in a chemical detonator, the method including loading a timer charge, a sealing charge, a priming charge and a base charge in a tubular casing, the charges being loaded into the casing to form a series with the sealing charge at one end of the series, the sealing charge being in contact with the timer charge, the timer charge being in contact with the priming charge, and the priming charge being in contact with the base charge, which is at the opposite end of the series.
17. A method according to claim 16 wherein the timer charge is loaded first, through an end of the casing, and is loaded into contact with a plunger which has been inserted into the end of the casing opposite the end of the casing through which the timer charge is loaded.
18. A method according to claim 17 wherein loading of the timer charge is followed by loading of the sealing charge, which is followed in turn by loading of the priming charge and then by loading of the base charge, the charges being loaded so that the series occupies substantially the whole of the interior of the tubular casing, with the sealing charge and base charge at opposite ends of the casing, the sealing charge being loaded, with the plunger in place, through the same end of the casing as the timer charge and the priming charge and the base charge, after withdrawal of the plunger from the casing, being loaded through the opposite end of the casing.
19. A method according to claim 18, in which the casing is straight and upright during the loading, the charges being loaded vertically into the casing.
20. A method according to claim 19 in which the timer charge and sealing charge are loaded downwardly into the casing and, after loading of the timer charge and the sealing charge, the casing is inverted, the priming charge and the base charge being loaded downwardly into the casing, the end of the casing through which the timer charge and sealing charge are loaded being narrowed by crimping it inwardly, after loading of the sealing charge and before loading of the priming charge, to hold the timer charge and the sealing charge in the casing during loading of the priming charge and during loading of the base charge.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AP2008004608A AP2640A (en) | 2006-03-24 | 2007-03-22 | Detonation of explosives |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ZA2006/02425 | 2006-03-24 | ||
ZA200602425 | 2006-03-24 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2007110819A1 true WO2007110819A1 (en) | 2007-10-04 |
Family
ID=38328619
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2007/051008 WO2007110819A1 (en) | 2006-03-24 | 2007-03-22 | Detonation of explosives |
Country Status (5)
Country | Link |
---|---|
AP (1) | AP2640A (en) |
AR (1) | AR060093A1 (en) |
PE (1) | PE20071298A1 (en) |
WO (1) | WO2007110819A1 (en) |
ZA (1) | ZA200808037B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013059841A1 (en) * | 2011-10-17 | 2013-04-25 | Ael Mining Services Limited | Pyrotechnic time delay element |
EP2589582A3 (en) * | 2011-07-28 | 2016-01-06 | Austin Detonator s.r.o. | Pyrotechnic millisecond delay charge for industrial detonators with delay time of explosion of 25 to 1,000 ms from initiation, the way of manufacture of the delay charge, and electric and non-electric detonator |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3306201A (en) * | 1965-06-30 | 1967-02-28 | Du Pont | Explosive composition and waterhammer-resistant delay device containing same |
EP0304973A1 (en) * | 1987-07-29 | 1989-03-01 | Schweizerische Eidgenossenschaft vertreten durch die Eidg. Munitionsfabrik Thun der Gruppe für Rüstungsdienste | Pyrotechnic delay element for delay fuzes and its use |
FR2642158A1 (en) * | 1989-01-20 | 1990-07-27 | Bickford Snc Davey | Process for preparing a delay assembly for a detonator and delay assembly |
WO2002072504A1 (en) * | 2001-03-09 | 2002-09-19 | Orica Explosives Technology Pty Ltd | Delay compositions and detonation delay devices utilizing same |
US20040055494A1 (en) * | 2002-09-25 | 2004-03-25 | O'brien John P. | Detonator junction for blasting networks |
-
2007
- 2007-03-22 WO PCT/IB2007/051008 patent/WO2007110819A1/en active Application Filing
- 2007-03-22 AP AP2008004608A patent/AP2640A/en active
- 2007-03-22 PE PE2007000313A patent/PE20071298A1/en not_active Application Discontinuation
- 2007-03-23 AR ARP070101216A patent/AR060093A1/en active IP Right Grant
-
2008
- 2008-09-18 ZA ZA200808037A patent/ZA200808037B/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3306201A (en) * | 1965-06-30 | 1967-02-28 | Du Pont | Explosive composition and waterhammer-resistant delay device containing same |
EP0304973A1 (en) * | 1987-07-29 | 1989-03-01 | Schweizerische Eidgenossenschaft vertreten durch die Eidg. Munitionsfabrik Thun der Gruppe für Rüstungsdienste | Pyrotechnic delay element for delay fuzes and its use |
FR2642158A1 (en) * | 1989-01-20 | 1990-07-27 | Bickford Snc Davey | Process for preparing a delay assembly for a detonator and delay assembly |
WO2002072504A1 (en) * | 2001-03-09 | 2002-09-19 | Orica Explosives Technology Pty Ltd | Delay compositions and detonation delay devices utilizing same |
US20040055494A1 (en) * | 2002-09-25 | 2004-03-25 | O'brien John P. | Detonator junction for blasting networks |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2589582A3 (en) * | 2011-07-28 | 2016-01-06 | Austin Detonator s.r.o. | Pyrotechnic millisecond delay charge for industrial detonators with delay time of explosion of 25 to 1,000 ms from initiation, the way of manufacture of the delay charge, and electric and non-electric detonator |
CZ306594B6 (en) * | 2011-07-28 | 2017-03-22 | Austin Detonator S.R.O. | A millisecond delay pyrotechnic composition for industrial detonators with explosion delay time of 25-1000 ms from the initiation, the method of manufacturing the delay composition and an electric and non-electric detonator |
WO2013059841A1 (en) * | 2011-10-17 | 2013-04-25 | Ael Mining Services Limited | Pyrotechnic time delay element |
Also Published As
Publication number | Publication date |
---|---|
AP2640A (en) | 2013-04-11 |
PE20071298A1 (en) | 2008-02-06 |
AP2008004608A0 (en) | 2008-10-31 |
ZA200808037B (en) | 2009-11-25 |
AR060093A1 (en) | 2008-05-21 |
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