Ammunition and explosives – Igniting devices and systems – Electrical primer or ignitor
Reexamination Certificate
2000-03-06
2002-05-21
Nelson, Peter A. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Electrical primer or ignitor
C102S301000, C102S302000
Reexamination Certificate
active
06389973
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a blasting apparatus and a blasting method in which a fusible and vaporizable substance (for example, a thin metal wire is used) is fused and vaporized by supplying electrical energy to the fusible and vaporizable substance for a short period of time, and nitromethane is detonated by a phenomenon in the process accompanying this fusing and vaporizing, whereby an object to be blasted such as a concrete structure and rock-bed is blasted.
1. Background Art
There has conventionally been available a blasting apparatus for blasting an object to be blasted such as a concrete structure and rock-bed, which has dynamite and a detonator used as means for detonating the dynamite.
The dynamite uses a low explosive which is not readily detonated when some impact force is applied or when fire is taken in order to assure safety in handling. For this reason, the detonator is filled with an explosive which is detonated relatively easily. The explosive charged in the detonator is detonated by fire or electrical spark, and the low explosive used in the dynamite is detonated by a shock occurring at this time. However, since the detonator is filled with an explosive which is detonated relatively easily, there is a danger that the detonator will be detonated if a leak current from an equipment around the storage place, a surge current, a thunderbolt or the like occurs and such a current is supplied to the detonator.
Accordingly, an object of the present invention is to provide a blasting apparatus and a blasting method which can solve the above problem.
2. Disclosure of the Invention
The present invention provides a blasting apparatus comprising a blasting vessel charged with nitromethane and mounted in an object to be blasted, a fusible and vaporizable substance which is exposedly provided in this nitromethane and suddenly fuses and vaporizes by being supplied with a predetermined amount of electrical energy for a short period of time, and an electrical energy supply circuit having a capacitor for accumulating the predetermined amount of electrical energy to be supplied to the fusible and vaporizable substance, wherein when the predetermined amount of electrical energy is supplied, the nitromethane is detonated by a phenomenon in the process in which the fusible and vaporizable substance fuses and vaporizes, so that the object to be blasted is blasted by the detonation force.
According to the configuration of the present invention, when the predetermined amount of electrical energy is accumulated in the capacitor, and the electrical energy is supplied from the electrical energy supply circuit to the fusible and vaporizable substance, the fusible and vaporizable substance suddenly fuses and vaporizes, and the nitromethane is detonated by a phenomenon in the process in which the fusible and vaporizable substance fuses and vaporizes, so that the object to be blasted is blasted by this detonation force. Even if a leak current from a surrounding equipment occurs, the nitromethane is not detonated unless electrical energy enough to fuse and vaporize the fusible and vaporizable substance is supplied, so that the safety in handing the blasting apparatus can be improved.
Also, the present invention provides a blasting apparatus using nitromethane. In this case as well, since the nitromethane is not detonated unless electrical energy enough to fuse and vaporize the fusible and vaporizable substance is supplied, the safety in handing the blasting apparatus is improved, and since a strong blasting force is obtained by detonating the nitromethane, the object to be blasted can surely be blasted or made brittle.
Also, the present invention provides a blasting method comprising the steps of exposedly providing a fusible and vaporizable substance in nitromethane charged in a blasting vessel, said fusible and vaporizable substance suddenly fusing and vaporizing by being supplied with a predetermined amount of electrical energy for a short period of time, supplying electrical energy enough to fuse and vaporize the fusible and vaporizable substance to this fusible and vaporizable substance from a capacitor, and detonating the nitromethane by a phenomenon in the process in which the fusible and vaporizable substance fuses and vaporizes so that an object to be blasted is blasted by this detonation force, wherein as conditions for detonating the nitromethane, the charging voltage V
c
(V), charging energy W (J) and capacitance C (F) of the capacitor are set to have the following relationship:
V
c
≧1000 (V)
W
=(½)·
C·
V
c
2
≧250 (J)
By thus setting the relationship of the charging voltage V
c
(V), charging energy W (J) and capacitance C (F) of the capacitor, the nitromethane near the fusible and vaporizable substance is detonated without fail, and the remaining nitromethane is detonated in succession by the resultant impact force, whereby the object to be blasted is blasted without fail.
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patent: 5115743 (1992-05-01), Loffler
patent: 5287791 (1994-02-01), Chaboki et al.
patent: 5429387 (1995-07-01), Clark et al.
patent: 5488908 (1996-02-01), Gilpin et al.
patent: 2362361 (1978-04-01), None
patent: 56-53398 (1981-05-01), None
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International Publication No. WO 97/06402, dated Feb. 20, 1997, International application No. PCT/US96/12749, Bolinas Technologies, Inc., Applicant; 71 pages, 20 sheets of drawings, International Search Report —3 pages.
Arai Hiroaki
Maehata Hidehiko
Tamakoshi Daisuke
Hitachi Zosen Corporation
Jaffe Michael A.
Kusner Mark
Nelson Peter A.
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