Title:
Safe electrical initiation plug for electric detonators
Kind Code:
A1


Abstract:
A device for initiating an electric detonator utilizing an open circuit to decrease occurrences of accidental detonation. The device may include an initiator housing, at least two conductor pins disposed through the initiator housing and spaced within the housing such that they are electrically isolated from one another, and a primer spot material disposed between the conductor pins. The primer spot material may be comprised of a mixture of reactive material and metal component. The primer spot material has electrical properties which provide resistance to conducting an electrical current to maintain an open circuit condition prior to occurrence of a breakdown voltage which is dependent upon the amount of metal component in the primer spot material. Subsequently, the primer spot material has electrical properties which provide a conductive medium on the occurrence of an electrical arc between the conductive pins that arises at voltages in excess of the breakdown voltage. Finally, the electrical properties are such that the electrical arc provides energy to form a plasma from the primer spot material, leading to initiation of the detonator.



Inventors:
Ofca, William W. (Hyde Park, NY, US)
Application Number:
10/444389
Publication Date:
11/25/2004
Filing Date:
05/23/2003
Assignee:
OFCA WILLIAM W.
Primary Class:
International Classes:
F42B3/18; F42B3/198; (IPC1-7): F42C19/12
View Patent Images:
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Primary Examiner:
CHAMBERS, TROY
Attorney, Agent or Firm:
THORPE NORTH & WESTERN, LLP. (SANDY, UT, US)
Claims:

What is claimed is:



1. An explosive initiation device, for initiating an electric detonator utilizing an open circuit to decrease occurrences of accidental detonation, comprising: a) an initiator housing; b) at least two conductor pins disposed through the initiator housing, spaced within the housing such that the conductor pins are electrically isolated from one another; and c) primer spot material disposed between the conductor pins, said primer spot material comprising a mixture of reactive material and metal component, such that the primer spot material has electrical properties which provide resistance to conducting electrical current to maintain an open circuit condition up to a breakdown voltage dependent upon an amount of metal component in the primer spot material, and which provides a subsequent conductive medium on occurrence of an arc between the conductive pins that arises at voltages in excess of the breakdown voltage, whereby said arc provides energy to form a plasma from the primer spot material.

2. An initiation device in accordance with claim 1, wherein the primer spot material comprises a mixture of HMX explosive and from about 8% to about 12% aluminum particles by weight.

3. An initiation device in accordance with claim 2, wherein the primer spot material further comprises about 5% to about 15% graphite particles by weight.

4. An initiation device in accordance with claim 1, wherein the primer spot material comprises a mixture of HMX explosive and about 10% aluminum particles by weight.

5. An initiation device in accordance with claim 1, wherein the primer spot material is a mixture of HMX explosive and about 9% aluminum particles by weight and about 9% graphite particles by weight.

6. An initiation device in accordance with claim 1, further comprising a detonator shell containing a base charge, wherein the initiator housing is received within and coupled to the detonator shell, where the primer spot material is located in a direction extending toward the base charge.

7. An initiation device in accordance with claim 1, further comprising a ferrule with an initiator housing end and a detonator end, wherein the initiator housing end is configured to couple with the initiator housing, and the detonator end is configured to couple with a detonator.

8. A method of manufacturing an electric initiation element for a detonator with a variable range of initiation voltages, comprising the following steps: a) providing an initiator housing; b) disposing at least two conductor pins through the initiator housing, said conductor pins being spaced within the initiator housing such that they are electrically isolated from one another; c) providing a reactive material useful as part of a primer spot material; d) determining an amount of conductive component to achieve a range of conduction initiation voltages; e) mixing the reactive material and the conductive component to form a primer spot material; and f) disposing the primer spot material between the conductor pins, said primer spot material having electrical properties which provide resistance to conducting electrical current to maintain an open circuit condition prior to occurrence of a breakdown voltage dependent upon the amount of conductive component in the primer spot material, and which provides a subsequent conductive medium on occurrence of an arc between the conductive pins that arises at voltages in excess of the breakdown voltage, whereby said arc provides energy to form a plasma from the primer spot material.

9. A method of manufacturing an electric initiation element for a detonator as in claim 8, further comprising the step of coupling a ferrule to the initiator housing, such that the primer spot material is located within the ferrule.

10. A method of manufacturing an electric initiation element for a detonator as in claim 9, wherein the step of disposing primer spot material between the conductor pins comprises the following steps: a) creating a slurry of primer spot material and lacquer; and b) applying the slurry to the conductor pins within the ferrule.

11. A method of manufacturing an electric initiation element for a detonator as in claim 9, further comprising the step of coupling the ferrule to a detonator.

12. A method of manufacturing an electric initiation element for a detonator, comprising the following steps: a) providing an initiator housing; b) disposing at least two conductor pins through the initiator housing, said conductor pins being spaced within the initiator housing such that they are electrically isolated from one another; and c) disposing primer spot material between the conductor pins, said primer spot material having electrical properties which provide resistance to conducting electrical current to maintain an open circuit condition, and which provides a subsequent conductive medium on occurrence of an arc between the conductive pins, whereby said arc provides energy to form a plasma from the primer spot material.

13. A method of manufacturing an electric initiation element for a detonator as in claim 12, further comprising the step of coupling a ferrule to the initiator housing, such that the primer spot material is located within the ferrule.

14. A method of manufacturing an electric initiation element for a detonator as in claim 13, wherein the step of disposing primer spot material between the conductor pins comprises the following steps: a) creating a slurry of primer spot material and lacquer; and b) applying the slurry to the conductor pins within the ferrule.

15. A method of manufacturing an electric initiation element for a detonator as in claim 13, further comprising the step of coupling the ferrule to a detonator.

16. A method of initiating an electric detonator, comprising the following steps: a) providing an open circuit across a primer spot material comprising a mixture of a reactive material and a metal component; b) applying a sufficiently high voltage to the open circuit to cause the primer spot material to ionize, thus creating a conductive medium; c) maintaining the voltage across the conductive medium to cause the metal component to vaporize and form a plasma gas, thus creating heat and a shockwave; and d) maintaining the voltage across the conductor medium to allow current to flow by means of the plasma gas thus creating a plasma gas arc, the plasma gas arc causing the reactive material to react, thus boosting the heat and the shockwave in a direction towards a detonator charge to initiate the detonator charge.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to detonation devices for use in the detonation of explosives. More particularly, the present invention relates to electric initiation plugs.

[0003] 2. Related Art

[0004] Detonators are used to initiate numerous types of explosive charges, from industrial to military settings. One precise and easily controlled detonation system utilizes electric current to initiate the explosive charge. These electric detonators typically consist of an elongated shell with an electrical ignition element at one end and an explosive base charge enclosed at the other end. External initiator leads extend through the ignition element and into the detonator interior, facing towards the base charge. A small bridge wire extends across the ends of the initiator leads, and is usually covered with a small amount of explosive material. In order to detonate the device, electrical current is introduced across the initiator leads. The small diameter of the bridge wire creates resistance to the flow of electrical current, generating heat. If the heat exceeds a critical temperature, the explosive material reacts, initiating the explosive reaction that will ultimately cause the detonation of the base charge. Additionally, a delay element may be disposed between the ignition element and the base charge to regulate the time between the initiation of the explosive reaction and the detonation of the base charge.

[0005] The design of electric detonators utilizing the heating of a bridge wire allows low electrical current signals to be employed. This creates safety issues regarding the premature detonation of these devices. One of these issues relates to static electricity buildup. Static electricity from the environment or the individual using the detonator may build up in the initiation leads and be discharged through the bridge wire, causing premature initiation of the explosive reaction and the detonation of the base charge, thus creating a potentially dangerous situation for those individuals in the vicinity of the blast. One method utilized in an attempt to nullify this potentially dangerous situation involves a shunt disposed across the initiator leads to discharge static buildup. Another method involves grounding the initiator leads to the shell of the detonator and to ground, effectively discharging the static electricity away from the bridge wire. These safety measures must be removed prior to detonation, however, creating a potentially dangerous situation at this point.

[0006] Another major safety issue involved with electric detonators concerns RF radiation from radios and cell phones. If the length of the initiator leads is a multiple of the wavelength of the RF radiation the leads may act as antennas, causing a small current to flow through the bridge wire and initiating the explosive reaction. One method utilized in an attempt to reduce the safety hazards inherent to RF radiation minimizes the antenna affect of the initiator leads by winding them into a bundle to reduce their length. The aforementioned safety methods relating to static electricity, namely utilizing a shunt across the initiator leads and grounding the initiator leads to the detonator shell, also serve to reduce the flow of small currents associated with RF radiation across the bridge wire. When the detonator is readied for use, however, the initiator leads must be unwound and the shunts and grounding devices removed, creating a potentially dangerous situation for the operator.

[0007] Another safety issue may arise to individuals not associated with the blasting operation. Some blasting, especially seismic gas and oil exploration, may be conducted in areas where the public has a great deal of access. The detonators may be buried in the ground well in advance of the scheduled blasting while other associated but remote sites are similarly prepared. In the interim between the placement of the detonator and the detonation of the explosives the public may have access to the site. If the initiator leads are found, the detonator can be exploded by something as simple as a 1{fraction (1/2)} Volt battery.

[0008] The safety issues relating to the detonation of explosives are significant, and the explosives field has generally attempted to solve these issues by developing mechanical measures such as shunting and grounding to eliminate them. This is an effective technique while the detonators are in transit, but these potential dangers return when the safety measures are removed when they are being prepared for use.

SUMMARY OF THE INVENTION

[0009] Conventional detonator safety methods do not entirely eliminate the threat of premature initiation. When the detonator is being coupled to an explosive and otherwise prepared for use the devices utilized to provide safety protection need to be removed. During this period of time the user of the detonator is at potential risk. The present invention provides an initiation plug that requires high voltage and high electrical current to activate, thus reducing accidents caused by low voltage/low current sources.

[0010] The present invention provides an initiation device for initiating an electric detonator utilizing an open circuit to decrease occurrences of accidental detonation. The device may include an initiator housing, at least two conductor pins disposed through the initiator housing and spaced within the housing such that they are electrically isolated from one another, and a chemical primer spot material disposed between the conductor pins. The primer spot material may be comprised of a mixture of reactive material and metal and/or conductive non-metal components. The primer spot material has electrical properties which provide resistance to conducting an electrical current to maintain an open circuit condition prior to occurrence of a breakdown voltage which is dependent upon the amount of metal and other conductive components in the primer spot material. Subsequently, the primer spot material has electrical properties which provide a conductive medium on the occurrence of an electrical arc between the conductive pins that arises at voltages in excess of the breakdown voltage. Finally, the electrical properties are such that the electrical arc provides energy to form a plasma from the primer spot material, leading to initiation of the detonator.

[0011] Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a cross-sectional view of a device for initiating an electric detonator in accordance with an embodiment of the present invention;

[0013] FIG. 2 is a cross-sectional view of another embodiment of a device for initiating an electric detonator in accordance with the present invention;

[0014] FIG. 3 is a flowchart of a method of manufacturing an electric initiation element for a detonator with a variable range of initiation voltages in accordance with an embodiment of the present invention;

[0015] FIG. 4 is a flowchart of a method of manufacturing an electric initiation element for a detonator in accordance with an embodiment of the present invention; and

[0016] FIG. 5 is a flowchart of a method of initiating an electric detonator in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

[0017] Reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles of the inventions as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention.

[0018] One of the major problems confronting those working in ihe explosives industry is the premature detonation of an explosive charge due to static electricity, RF radiation from radio transmitters, cellular phones, etc. To address this problem, the inventor has developed an electrical initiation device that requires energy stored in a capacitor that, when applied to cause initiation, is significantly greater than the energy created by static electricity or RF radiation.

[0019] FIGS. 1 and 2 show cross-sectional views of an explosive initiation device for initiating an electric detonator utilizing an open circuit to decrease occurrences of accidental detonation according to embodiments of the present invention. The initiation device 10 may include an initiator housing 12 and at least two conductor pins 14. The conductor pins 14 may be disposed through the initiator housing 12, spaced within the housing such that the conductor pins 14 are electrically isolated from one another. The conductor pins 14 may be made of a conductive material, an example of which is copper clad iron wire. The initiator housing 12 may be made from a nonconductive material such as plastic, rubber, glass or other insulating material in order to electrically isolate the conductor pins 14. Alternatively, embodiments of this invention contemplate an initiator housing 12 made from a conductive material with a nonconductive insert surrounding the conductor pins 14 thus achieving electrical isolation.

[0020] This example embodiment of the initiation device 10 may also include primer spot material 16 disposed between the conductor pins 14. The primer spot material 16 may be comprised of a mixture of a reactive material and a metal component or a metal together with other non-metal conductive materials. The reactive material may be an explosive, examples of which may be, but are not limited to, HMX, RDX, and PETN, and any crystalline powder explosive in admixtures with each other and in mixtures of oxidizing chemicals. The metal component may be a variety of conductive materials. For example, but not by way of limitation, aluminum powder, iron powder, steel powder, magnalium alloy, magnesium, or any combination of these materials. In addition, the metal component may include other conductive components, such as graphite, carbon, charcoal, zirconium, or any other conductive material with similar functional properties. For example, the primer spot material may include a mixture of HMX explosive and from about 8% to about 12% aluminum particles by weight. More specifically, a primer spot material mixture may be comprised of HMX explosive and about 10% aluminum particles by weight. Significant functional reliability has been achieved with a mixture of HMX explosive and 9% each of aluminum powder and graphite powder.

[0021] The primer spot material 16 has electrical properties which provide resistance to conducting electrical current to maintain an open circuit condition up to a breakdown voltage which is dependent upon the amount of conductive component in the primer spot material. Subsequently, the primer spot material 16 has electrical properties which provide a conductive medium on occurrence of an electrical arc between the conductive pins that arises at voltages in excess of the breakdown voltage. Finally, the electrical properties are such that the electrical arc provides energy to form a plasma from the primer spot material.

[0022] FIG. 1 shows an embodiment of the initiation device 10 in which a ferrule 19 is coupled to the initiator housing 12 at one end to enclose and hold the primer spot material 16. As further shown in FIG. 2, one embodiment of the initiation device 10 may further include a detonator housing 18 coupled to the initiator housing 12. The primer spot material is contained by the detonator housing 18 in a position which is directed towards a primary explosive 22 followed by a base charge 24 of initiator explosive. The initiation device 10 may be inserted into the detonator housing 18 with or without a ferrule 19 attached.

[0023] FIG. 3 is a flow chart of a method 30 of manufacturing an electric initiation element for a detonator with a variable range of initiation voltages according to an embodiment of the present invention. The first step 32 of the method 30 may include providing an initiator housing. The second step 34 of the method 30 may include disposing at least two conductor pins through the initiator housing. The conductor pins may be spaced within the initiator housing such that they are electrically isolated from one another, forming an open circuit. In one embodiment of the invention, conductor pins spaced at about {fraction (1/10)} inch apart (±0.005) produced good results. The open circuit assures that low electrical current from sources such as static electricity, RF radiation, and stray currents induced into the wire leads will be insufficient to cause initiation. The conductor pins may be made of a conductive material, an example of which is copper clad iron wire. The initiator housing may be made from a nonconductive material such as plastic, rubber, glass or other insulating material in order to electrically isolate the conductor pins. Alternatively, embodiments of this invention contemplate an initiator housing made from a conductive material with a nonconductive insert surrounding the conductor pins thus achieving electrical isolation.

[0024] The third step 36 of the method 30 may include providing a reactive material. The reactive material may be an explosive, examples of which may be, but are not limited to, HMX, RDX, PETN, and any crystalline powder explosive in admixtures with each other and in mixtures of oxidizing chemicals. The fourth step 38 of the method 30 may include determining an amount of conductive component to achieve a range of conduction initiation voltages. The conductive component may be a variety of conductive materials. For example, but not by way of limitation, aluminum powder, iron powder, steel powder, magnalium alloy, magnesium, zirconium, graphite, carbon, charcoal, any combination of these materials, or any other conductive material with similar functional properties. The fifth step 40 of the method 30 may include mixing the reactive material and the conductive component to form a primer spot material. The initiation voltage is defined as the voltage at which the open circuit experiences breakdown with conduction of electrical current. The primer spot material has electrical properties which provide resistance to conducting electrical current to maintain the open circuit condition up to the breakdown voltage. The breakdown voltage is dependent upon the amount of conductive component in the primer spot material, and may be altered by varying the amount of conductive component that is mixed with the reactive material to form the primer spot material. Additionally, the primer spot material has electrical properties which provide a subsequent conductive medium on occurrence of an electrical arc between the conductive pins that arises at voltages in excess of the breakdown voltage. Finally, the electrical properties are such that the electrical arc provides energy to form a plasma from the primer spot material.

[0025] The sixth step 42 of the method 30 may include coupling a ferrule to the initiator housing. In a subsequent step 44, a slurry may be created from the primer spot material and a lacquer such as, but not limited to, a nitrocellulose lacquer. The slurry may then be applied 46 to the conductor pins within the ferrule. The method of disposing the primer spot material between the conductor pins is not limited herein, and may be accomplished by any means known in the art.

[0026] Additionally, a detonator may be coupled 48 to the ferrule. In one embodiment of the invention, the ferrule and initiator housing may be inserted into a detonator housing. This method should in no way be limited by the use of the ferrule, and it is contemplated that other means of containing the primer spot material and coupling the initiator to the detonator are included within its scope.

[0027] FIG. 4 is a flow chart of a method 60 of manufacturing an electric initiation element for a detonator. The first step 62 of the method 60 may include providing an initiator housing. The second step 64 of the method 60 may include disposing at least two conductor pins through the initiator housing. The conductor pins may be spaced within the initiator housing such that they are electrically isolated from one another, forming an open circuit. The open circuit assures that low power energy sources such as static electricity and RF radiation will be insufficient to cause initiation. The conductor pins may be made of a conductive material, an example of which is copper clad iron wire. The initiator housing may be made from a nonconductive material such as plastic, rubber, glass or other insulating material in order to electrically isolate the conductor pins. Alternatively, embodiments of this invention contemplate an initiator housing made from a conductive material with a nonconductive insert surrounding the conductor pins thus achieving electrical isolation.

[0028] The third step 66 of the method 60 includes coupling a ferrule to the initiator housing. In a subsequent step 68, a slurry may be created from primer spot material and a lacquer such as, but not limited to, a nitrocellulose lacquer. The slurry may then be applied 70 to the conductor pins within the ferrule. The primer spot material may be comprised of a mixture of a reactive material and a metal component. The reactive material may be an explosive, examples of which may be, but are not limited to, HMX, RDX, and PETN, and any crystalline powder explosive in admixtures with each other and in mixtures of oxidizing chemicals. The metal component may be a variety of conductive materials. For example, but not by way of limitation, aluminum powder, iron powder, steel powder, magnalium alloy, magnesium, zirconium, graphite, carbon, charcoal, any combination of these materials, or any other conductive material with similar functional properties. The primer spot material has electrical properties which provide resistance to conducting electrical current to maintain an open circuit condition. Subsequently, the primer spot material has electrical properties which provide a conductive medium on occurrence of an electrical arc between the conductive pins. Finally, the electrical properties are such that the electrical arc provides energy to form a plasma from the primer spot material.

[0029] Additionally, a detonator may be coupled 72 to the ferrule. In one embodiment of the invention, the ferrule and initiator housing may be inserted into a detonator housing. This method should in no way be limited by the use of the ferrule, and it is contemplated that other means of containing the primer spot material and coupling the initiator to the detonator are included within its scope.

[0030] FIG. 5 is a flow chart of a method 80 of initiating an electric detonator. The first step 82 of the method 80 may include providing an open circuit across a primer spot material. The primer spot material may be comprised of a mixture of a reactive material and a conductive component. The reactive material may be an explosive, examples of which may be, but are not limited to, HMX, RDX, and PETN, and any crystalline powder explosive in admixtures with each other and in mixtures of oxidizing chemicals. The conductive component may be a variety of conductive materials. For example, but not by way of limitation, aluminum powder, iron powder, steel powder, magnalium alloy, magnesium, zirconium, graphite, carbon, charcoal, any combination of these materials, or any other conductive material with similar functional properties. The second step 84 of the method 80 may include applying a sufficiently high voltage to the open circuit to cause the primer spot material to ionize. The sufficiently high voltage may be a DC current supplied by a charged capacitor that is applied across the primer spot material at a negative input region and a positive input region. The primer spot material close to the negative input region gets an abundance of electrons and becomes negatively charged. Likewise, the primer spot material near the positive input region has electrons drawn away, and the absence of electrons causes it to become positively charged. The atoms within the primer spot material that are effectively charged by this process are the metal component, the reactive material, the air gaps between the metal component and the reactive material, and also the air above the primer spot material near the negative and positive input regions. The reactive material may be non-conductive or a good insulator. Like any insulator, including air, it will break down and conduct under the energy of the right voltage. Thus the application of a sufficiently high voltage DC current across the primer spot material to cause it to ionize and break down creates a conductive medium from the previously open circuit.

[0031] The level of voltage to create ionization, breakdown and consequent conduction is variable and dependent on two major considerations: (1) the formula of the primer spot material; and (2) the distance between the conductive pins.

[0032] The third step 86 of the method 80 may include maintaining the electrical current conduction after voltage breakdown across the conductive medium to cause the metal component to vaporize. The discharge of the high voltage DC current across the primer spot material creates high heat that melts and vaporizes the metal component into a plasma gas.

[0033] For example, when aluminum is used as the metal component, an aluminum oxide vapor gas is created at approximately 2,900 degrees Celsius. In addition to the high heat, a shockwave is created by the high voltage DC current when it arcs across the primer spot material. The reaction of the explosive material may contribute to this shockwave. The fourth step 88 of the method 80 may include maintaining the voltage across the conductor medium to allow the current to flow by means of the plasma gas. The resulting plasma gas arc with the accompanying high heat and shockwave causes a quantity of the reactive material to react, thus boosting the heat and the shockwave in a direction towards a detonator charge to initiate the detonator charge.

EXAMPLE

[0034] The following example represents an embodiment of the present invention, and is not intended to limit the scope of the invention.

[0035] Mixtures of primer spot material comprising HMX explosive with 10% aluminum by weight and variable amounts of graphite were tested for firing times.

[0036] The static test was 27 kilovolts charged on a 300 pfd capacitor and then switched to the pins of the plug. Only the 10% graphite formula did not spark or arc after multiple repeated tries on several different plugs. When 10% graphite is mixed with the HMX explosive with 10% aluminum, the resulting formula contains 82% HMX, 9% aluminum and 9% graphite by weight. The other formulas all sparked (arced) pin to pin on every try. This plug-only static test was a visual test, and those that displayed sparking indicated the potential to shoot a detonator, thus those plugs failed the test. When it was determined that a sample plug failed the static test no further testing was considered, thus explaining the n/a entries in Table 1.

[0037] The Max. No Fire test represents the maximum AC or DC voltage that can be applied with absolutely no reactions observed in the initiation element, including sparking or smoking. The Min. All Fire test represents the minimum DC voltage that can be applied that will cause all initiation plugs to fire.

[0038] All DC voltage function time testing was accomplished by charging a 470 microfarad capacitor to 650 V, and then switching the charged capacitor to the pins of the plug. The AC voltage testing was accomplished with a variac capable of 0 to 140 VAC adjustable. All tests were conducted with 4 foot test leads directly attached to the plugs, except for the 200 foot spool test. The 200 foot spool was 21 gage solid copper duplex wire. Finally, the resistance of pin to pin was obtained with a 500 VDC megohmmeter. The results of these tests are shown in Table 1. 1

TABLE 1
Plug Firing Tests.
HMX/AlHMX/AlHMX/AlHMX/Al
Test DataNo Graphite5% Graphite10% Graphite15% Graphite
Static TestFailedFailedPassedFailed
Avg. Timing34.0 μs2.2 μs1.4 μs14.6 μs
650 VDC
Timing Range1.6 μs-136.6 μs1.9 μs-2.7 μs0.6 μs-6.8 μs0.9 μs-34.0 μs
650 VDC
Avg. ResistanceInfinite22.1 k ohm7.7 k ohm43.7 k ohm
500 VDC
Max. No Fire140 VAC120 VAC110 VAC130 VAC
AC Voltage
Max. No Firen/a160 VDC140 VDCn/a
DC Voltage
Min. All Firen/a250 VDC220 VDCn/a
DC Voltage
200 Ft. Spooln/an/a4.1 μsn/a
Avg. Timing
200 Ft. Spooln/an/a3.2 μs-4.9 μsn/a
Timing Range

[0039] It is to be understood that the above-referenced arrangements are illustrative of the application for the principles of the present invention. Numerous modifications and alternative arrangements can be devised without departing from the spirit and scope of the present invention while the present invention has been shown in the drawings and described above in connection with the exemplary embodiments(s) of the invention. It will be apparent to those of ordinary skill in the art that numerous modifications can be made without departing from the principles and concepts of the invention as set forth in the claims.