(19)
(11)EP 3 292 093 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
22.07.2020 Bulletin 2020/30

(21)Application number: 16716951.5

(22)Date of filing:  11.03.2016
(51)International Patent Classification (IPC): 
C06B 27/00(2006.01)
C06C 9/00(2006.01)
C06B 43/00(2006.01)
(86)International application number:
PCT/US2016/021985
(87)International publication number:
WO 2016/178744 (10.11.2016 Gazette  2016/45)

(54)

IGNITION SYSTEM

ZÜNDSYSTEM

SYSTÈME D'ALLUMAGE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 02.05.2015 US 201562156247 P

(43)Date of publication of application:
14.03.2018 Bulletin 2018/11

(73)Proprietor: Aerojet Rocketdyne, Inc.
Sacramento, CA 95813-6000 (US)

(72)Inventor:
  • SCHLUETER, Samuel
    Sacramento, California 95813-6000 (US)

(74)Representative: Dehns 
St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
US-A- 3 729 935
US-A- 4 208 967
US-A1- 2012 055 594
US-A- 3 734 019
US-A- 5 042 386
  
  • Anonymous: "Sigmund Cohn - Pyrofuze", , 24 February 2015 (2015-02-24), XP055276018, Retrieved from the Internet: URL:https://web.archive.org/web/2015022422 0550/http://sigmundcohn.com/internal.asp?p ageID=11 [retrieved on 2016-05-27]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

BACKGROUND



[0001] Pyrotechnic ignition materials are used for ignition in rocket motors. One example ignition material is boron potassium nitrate. Boron potassium nitrate has attractive handling characteristics; however, as an ignition material it has relatively low energy and ignition rate. While there are ignition materials that have higher energy and ignition rates, such materials fall short of the desired handling characteristics and thus cannot be used in substitute of boron potassium nitrate.

[0002] A prior art ignition system having the features of the preamble to claim 1 is disclosed in US 5,042,386.

SUMMARY



[0003] An ignition system according to the present disclosure includes a wire having an outer jacket encasing an inner core. The outer jacket includes palladium and ruthenium, and the inner core includes aluminum, and a fluorine-containing polymer coating on the wire.

[0004] In an embodiment of the foregoing, the outer jacket has, by weight, approximately 95% of palladium and approximately 5% of ruthenium.

[0005] In a further embodiment of any of the foregoing embodiments, the inner core has, by weight, approximately 95% of aluminum.

BRIEF DESCRIPTION OF THE DRAWINGS



[0006] The various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

Figure 1 illustrates an example of an ignition system that has a multi-metallic ignition body and a fluorine-containing body.

Figure 2 is another example of an ignition system in the form of a wire or filament, in accordance with the present invention.

Figure 3 is a sectioned view of the ignition system of Figure 2.

Figure 4 is another example ignition system in the form of a ribbon.

Figure 5 is an example of a method of fabricating an ignition system.


DETAILED DESCRIPTION



[0007] Figure 1 schematically illustrates a sectioned view of a representative portion of an ignition system 20. In this example, the ignition system 20 includes a multi-metallic ignition body 22 that has at least two metallic elements 24/26 in contact with each other. Although not limited, the metallic elements 24/26 are in contact at interface 28 in the example shown. The ignition system 20 further includes a fluorine-containing body 30 in contact with the multi-metallic ignition body 22. Although also not limited, the fluorine-containing body 30 is in contact with the multi-metallic ignition body 22 at interface 32 in the example shown.

[0008] In the illustrated example, the metallic elements 24/26 of the multi-metallic ignition body 22 and the fluorine-containing body 30 are each provided as layers. Such layers are generally of uniform thickness and can be flat or curved, for example. As will be appreciated given this disclosure, the metallic elements 24/26 of the multi-metallic ignition body 22 and/or the fluorine-containing body 30 may alternatively be provided in geometries other than layers.

[0009] The metallic elements 24/26, as well as additional metallic elements if present, are reactive with each other, in the absence of oxygen, above an ignition initiation temperature. When heated above the ignition temperature by electric current or other energy source the metallic elements react in an exothermic self-sustaining alloying reaction to generate heat. The self-sustaining alloying reaction proceeds until the alloying is complete. For instance, the alloying reaction is rapid and results in deflagration without the support of oxygen.

[0010] While the reaction between the metallic elements 24/26 alone releases heat, at least the fluorine in the fluorine-containing body 30 also reacts to augment thermal release beyond that of the metals alone. For example, the fluorine serves as an oxidant to react with the metallic elements, the reaction products of the metallic elements, or both in a pyrotechnic chemical reaction. The exothermic reactions between the metallic elements, the metallic elements with the fluorine, and/or the byproducts of the metallic elements and fluorine releases heat and generates hot gases. The hot gases may contain the metallic elements, metal fluorides, fluorine, and/or metal carbides of the metallic elements. The hot gases may be utilized to rapidly pressurize and ignite a grain material, such as a solid propellant grain material in a rocket motor.

[0011] In one example, the metallic elements 24/26 of the multi-metallic ignition body 22 are based upon at least palladium and aluminum. For example the metallic element 24 is aluminum or an aluminum-based alloy and the metallic element 26 is palladium or a palladium-based alloy. Although not limited, one example of a useful aluminum alloy is aluminum alloy 5056, which has, by weight, approximately 5% magnesium, approximately 0.12% manganese, approximately 0.12% chromium, and a remainder of aluminum and any impurities.

[0012] The multi-metallic ignition body 22 includes ruthenium as an additional, reactive metallic element. The ruthenium may be provided as an alloy with the palladium. In one example the palladium-ruthenium alloy includes, by weight, approximately 95% palladium and approximately 5% ruthenium.

[0013] The fluorine-containing body 30 is a fluorine-containing polymer. In accordance with the present invention, the fluorine-containing polymers are polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyvinylidene fluoride (PVF), hexafluoropropylene (HFP), polyvinylfluoride (PVD), polyethylenetetrafluoroethylene (ETFE), and combinations thereof.

[0014] Figure 2 depicts ignition system 120, which is also shown in a sectioned view in Figure 3. In this disclosure, like reference numerals designate like elements where appropriate and reference numerals with the addition of one-hundred or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding elements. The ignition system 120 is in the form of a wire or filament. The wire or filament includes a multi-metallic ignition body 122 that has two or more metallic elements 124/126 in contact with each other at interface 128. In this example, the metallic element 124 is provided as an inner core 124a and the metallic element 126 is provided as an outer jacket 126a that encases or circumscribes the inner core 124a. The outer jacket 126a may include palladium or palladium-ruthenium alloy as described above, and the inner core 124a may include aluminum or aluminum alloy as described above. One example of the metallic elements 124/126 is PYROFUZE® (Sigmund Cohn Corp.).

[0015] The ignition system 120 further includes a fluorine-containing body 130 in the form of a fluorine-containing polymer coating 130a that is in contact at interface 132 with the multi-metallic ignition body 122. The fluorine-containing polymer coating 130a may include the fluorine-containing polymer as described above.

[0016] By encasing the multi-metallic ignition body 122, the fluorine-containing polymer coating 130a protects the multi-metallic ignition body 122 from moisture infiltration, foreign substance exposure, mechanical damage, and the like. The ignition system 120 thus provides enhanced handling characteristics in combination with high energy release and good ignition rate from the reaction between the metals and also the fluorine oxidizer.

[0017] In the example shown, the wire or filament is substantially circular in cross-section. Figure 4 illustrates another example ignition system 220 that is similar to the ignition system 120 but has a modified geometry. Rather than circular, the filament is flattened in the form of a ribbon. Although not limited, the examples herein may also be adapted to other geometries, such as pellets that have the jacket-core configuration. Additionally, filaments, ribbons, pellets, or other geometries can be combined or used to form other architectures, such as but not limited to, rolled structures, intertwined structures, braided structures, divided/chopped structures, pressed rope structures, pressed block structures, and the like.

[0018] Figure 5 illustrates an example method 150 of fabricating the ignition systems 20/120/220 described herein. At 152 the method 150 includes providing the multi-metallic ignition body 22/122 described herein. At 154 the method 150 includes bringing the fluorine-containing body 30/130 into contact with the multi-metallic ignition body 22/122. Although not limited, the step 154 may involve a shrink-wrapping technique or a deposition technique. In the shrink-wrapping technique, the fluorine-containing body 30/130 is provided as a tube or sleeve. For instance, the tube or sleeve is formed of the fluorine-containing polymer that is pre-stressed. The tube or sleeve is initially larger in size than the multi-metallic ignition body 22/122. The tube or sleeve is arranged around the multi-metallic ignition body 22/122 and then heated. The heat relaxes the pre-stressed polymer, causing the polymer to shrink and conform around the multi-metallic ignition body 22/122.

[0019] The deposition technique may include initially providing the fluorine-containing polymer as a liquid. The liquid is deposited onto the multi-metallic ignition body 22/122 and then solidified to form the fluorine-containing body 30/130. The manner of deposition may be varied depending on the selected geometry of the ignition systems 20/120/220. Non-limiting examples may include dipping and spraying. The manner of solidification may depend on the type of polymer selected. As examples, the solidification may include curing the polymer or cooling the polymer.

[0020] Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.

[0021] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.


Claims

1. An ignition system (20;120;220) comprising:

a wire having an outer jacket (126a) encasing an inner core (124a), the outer jacket (126a) including palladium and ruthenium, and the inner core (124a) including aluminum; and

a fluorine-containing polymer coating on the wire, characterised in that the fluorine-containing polymer coating is selected from a group consisting of polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyvinylidene fluoride (PVF), hexafluoropropylene (HFP), polyvinylfluoride (PVD), polyethylenetetrafluoroethylene (ETFE), and combinations thereof.


 
2. The ignition system (20;120;220) as recited in claim 1, wherein the outer jacket (126a) has, by weight, approximately 95% of palladium and approximately 5% of ruthenium.
 
3. The ignition system (20;120;220) as recited in claim 1, wherein the inner core (124a) has, by weight, approximately 95% of aluminum.
 


Ansprüche

1. Zündsystem (20; 120; 220), umfassend:

einen Draht, der einen Außenmantel (126a) aufweist, welcher einen Innenkern (124a) umgibt, wobei der Außenmantel (126a) Palladium und Ruthenium einschließt, und der Innenkern (124a) Aluminium einschließt; und

eine fluorhaltige Polymerbeschichtung auf dem Draht, dadurch gekennzeichnet, dass die fluorhaltige Polymerbeschichtung ausgewählt ist aus einer Gruppe bestehend aus Polytetrafluorethylen (PTFE), fluoriertem Ethylenpropylen (FEP), Polyvinylidenfluorid (PVF), Hexafluorpropylen (HFP), Polyvinylfluorid (PVD), Polyethylentetrafluorethylen (ETFE), und Kombinationen davon.


 
2. Zündsystem (20; 120; 220) nach Anspruch 1, wobei der Außenmantel (126a), auf das Gewicht bezogen, rund 95 % Palladium und rund 5 % Ruthenium aufweist.
 
3. Zündsystem (20; 120; 220) nach Anspruch 1, wobei der Innenkern (124a), auf das Gewicht bezogen, rund 95 % Aluminium aufweist.
 


Revendications

1. Système d'allumage (20; 120; 220) comprenant :

un fil métallique ayant une gaine extérieure (126a) renfermant une âme intérieure (124a), la gaine extérieure (126a) incluant du palladium et du ruthénium, et l'âme intérieure (124a) incluant de l'aluminium ; et

un revêtement de polymère contenant du fluor sur le fil métallique, caractérisé en ce que le revêtement de polymère contenant du fluor est choisi dans un groupe consistant en polytétrafluoroéthylène (PTFE), éthylène propylène fluoré (FEP), fluorure de polyvinylidène (PVF), hexafluoropropylène (HFP), fluorure de polyvinyle (PVD), polyéthylènetétrafluoroéthylène (ETFE), et leurs combinaisons.


 
2. Système d'allumage (20; 120; 220) selon la revendication 1, dans lequel la gaine extérieure (126a) a, en poids, environ 95 % de palladium et environ 5 % de ruthénium.
 
3. Système d'allumage (20; 120; 220) selon la revendication 1, dans lequel l'âme intérieure (124a) a, en poids, environ 95 % d'aluminium.
 




Drawing











Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description