Ammunition and explosives – Igniting devices and systems – Arming devices
Reexamination Certificate
1999-11-29
2001-08-07
Jordan, Charles T. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Arming devices
C102S262000, C102S221000, C102S222000, C102S200000
Reexamination Certificate
active
06269746
ABSTRACT:
SPONSORSHIP
This invention has not been made under any Federal or Independent sponsorship and is the individual result of the efforts of the Applicant.
RELATED APPLICATIONS
Applicant has not filed any previous application related to the subject matter of this application and is not aware of any applications that may be on file by other applicants that would relate to the subject matter of this application.
FIELD OF THE INVENTION
This application relates generally to the disarmament of explosive devices and more particularly to a mechanism for remotely disarming an explosive device by short-circuiting the connections to a detonator bridge and thus the detonator through a remote control to positively shift the detonator bridge control switch from an on to an off position with the capabilities of locking the same in the off or short circuit position to prevent expulsion of a suppressant material to a protected area. The application also includes structure for selectively connecting a source of pressure to the area containing the suppressant material.
SHORT SUMMARY OF THE INVENTION
A mechanism for remotely disarming an explosive device contained within a suppressant containing housing. One end of the housing is directed toward a rated or need to be protected area with the other end directed to a pressure source which will supply propelling force to the suppressant when the device is activated due to an impending explosion which is sensed by a rise in pressure in the protected area, or which could also be sensed through optical means being responsive to the characteristics of an impending explosion. The explosive device includes an intrinsically safe power supply or intrinsically safe connection to a power supply, a detonator and detonator bridge circuit with a switch between the supply and detonator and bridge, with the detonator arranged within the suppressant containing portion of the housing. Within this section a predetermined amount of extinguishing material is maintained.
Applicant's invention provides for non-mechanical control of the switch to short circuit the detonator bridge and prevent suppressant expulsion into the protected area and further includes a shiftable latching device for control of suppressant expelling air during the period when the detonator bridge and detonator is deactivated.
Applicant's equipment is designed to react to developing explosions that can occur inside of rated or process enclosures which may include combustible dusts, gases or vapors. It responds to the presence of a developing explosion after it starts and then delivers a suppression agent into the process volume to extract heat from the developing fireball, thus extinguishing the same before it grows to damaging proportions. The initial detonator explosion, resulting expulsion and propulsion of suppressant material will extract heat from and reduce the volume of a developing fireball from which an explosion forms and continued expulsion and propulsion of extinguishing material by the released air from the pressure source will extinguish the fireball and prevent damage.
The remote, non-electrical switch employs a magnetic field control to disconnect the detonator control bridge from electrical power and simultaneously short circuit the bridge. The switch is, selectively, of the reed type which is controllable by the position of a magnetic field relative thereto such that one position of the magnet will permit the contacts of the switch to maintain a closed position for power supply to the bridge and a manual rotation of the magnet toward the reed switch and aligned with the same by an external knob will open the connecteion to the power supply and simultaneously short circuit the detonator wires connected to the switch.
The lengths of wire between the power supply and the detonator bridge in the system are selected to eliminate the possibility that sufficient energy could be induced to such wires to actuate the detonator bridge.
In addition to the above, means is provided for an OSHA lockout device to be secured to the external knob, to prevent either intentional or accidental moving of the magnet and thus magnetic field from the Off position of the switch to its On position, and both local and remote signaling devices are provided to inform personnel as to condition and position of the switch.
BACKGROUND AND OBJECTS OF THE INVENTION
The Applicant has a long history of experience in the field of fire and explosion detection and control in processes involving agricultural dusts, pharmaceutical dusts, propane/air mixtures and other combinations characterized by a relatively long initial period of slow fireball growth prior to the “explosion” reaching its maximum rate of pressure increase and which are referred to as deflagrations. The equipment with which he is most familiar is not able to control the ignition (detonation) of high explosives, as, comparatively, they do not go through an initial period of relatively slow growth before reaching their maximum rate of pressure rise. The primary difference is that materials involved in a deflagration (slow initial rate of pressure rise) must seek out oxidizers contained in the air, and this process is accelerated as the fireball increases in surface area. In the case of detonation, the oxidizer is already mixed with the fuel, so the pressure rise is achieved almost instantaneously.
This invention then is directed to the control of a deflagration-type of “explosion” but this requires use of materials that will detonate to achieve suppression of a developing fireball, because the “relatively slow fireball growth rate” of the deflagration involves only milliseconds, the blink of an eye, and it has a head start on the counter measures.
The invention also considers at least one particular condition. In certain installations, it is often necessary to protect maintenance personnel that may be working in the “rated or protected” area, referred to as a hazardous area, from spurious discharge of explosion-response devices and certain, in-use, methods include mechanical blocking devices. These may cover those devices that utilize high discharge pressures in the range of 500 psig to 900 psig, where accidental discharge may create, not only a “scary” but dangerous situations, to maintenance personnel. With the Applicant's devices which utilize a low, 200 psig pressure level, an accidental discharge may be more “scary” than dangerous but this is still a concern of maintenance personnel.
It is well known in the field of explosives that detonators, including blasting caps, must have their connecting wires shorted to each other in order to prevent spurious discharge. This is necessary because wires serve as antenna which can pick up energy from various sources such as radio transmission waves or adjacent wires carrying alternating current. The result could be that sufficient energy is fed to the low resistance detonator bridge circuit that their coating of pyrotechnic material ignites, setting off the explosive train that is common to all detonators.
Applicant's invention provides a mechanism to remotely control the position of the moveable leaf of a reed switch to shift the same from an On, energy transmitting position, to an Off, short-circuiting position. Once so switched, an OSHA lockout can be coupled to prevent an accidental reestablishing of the circuit. During this period of disconnect, the invention may include a latching device to prevent release of air from a pressurized air source which could independently expel suppressant from the device.
The remote control basically consists of a rotatable magnet which is electrically and mechanically isolated from the switch, the switch and associated detonator being housed in a first housing section which contains a quantity of suppressant material which is discharged from the housing upon explosive discharge of the detonator. Such remote control magnet is mounted for rotation within a second housing section and has an external operating member such as a simple knob. To indicate to the person
Advanced Innovation, Inc.
Cwayna James R.
Jordan Charles T.
Semunegus Lulit
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