Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
  • F02K9/95—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof characterised by starting or ignition means or arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
  • F42C15/00—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges
  • F42C15/34—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges wherein the safety or arming action is effected by a blocking-member in the pyrotechnic or explosive train between primer and main charge

Definitions

• the invention relates to a safety igniter for igniting thrusters.
• the object of the invention is to achieve this aim and relates to a safety igniter for a thruster, the igniter comprising a primer (5) constituted by a primary pyrotechnic charge and a booster relay (1) comprising a secondary pyrotechnic charge, arranged in a relay body (2) forming an envelope; the igniter being characterized in that it further comprises:
• an igniter body (3) forming an envelope, in which a bore ( ⁇ ..) is produced substantially axially, the igniter body being disposed substantially along the same axis (xy) as the relay body (2) and being attached to the latter;
• FIG. 1 illustrates an embodiment of the igniter according to the invention in a safety configuration
• an igniter according to the invention comprises a primer (5) formed of a primary pyrotechnic charge.
• a booster relay (1) consisting of a secondary pyrotechnic charge.
• the latter is contained in a relay body (2) comprising a plurality of orifices (22) putting the igniter in communication with the device to be ignited, the propellant for example, of which only one element is seen in the figures ( 12).
• This relay body (2) is integral with the body of the igniter (3), itself made integral with the propellant by any known means.
• Safety requires that in the event of inadvertent ignition of the primer (5), means are provided so that the gases inadvertently emitted do not reach the reinforcing relay (1) and that this rupture of the pyrotechnic chain ignition prevents any incident which could lead to the unplanned ignition of the thruster.
• this result is obtained by ensuring the confinement of these gases so that they cannot precisely go to initiate the ignition booster relay (1).
• a passage allows the gases emitted by the primer (5) to reach the relay (1).
• the primer (5) is contained and fixed in a chamber, the envelope of which is a primer holder part (4) which is threaded through a bore of diameter ( ⁇ .,) Produced in the body (3) of the igniter. , and can slide in this bore ( ⁇ ..) along an axis (xy).
• this axis (xy) is substantially coincident with the axis of the relay body (2) and of the load (1).
• this primer holder part (4) has a so-called external shoulder (11) which abuts on a so-called internal shoulder (120) of the body (3) of the igniter when it is in the armed position c is to say operational ( Figure 2).
• the primer holder part (4) comprises at one of its ends, a bore ( ⁇ réelle) in which a centering base (44) is fitted, forming an integral part of the relay body (2) .
• this relay body (2) there is a channel (33) opening into a chamber (14) open to the secondary pyrotechnic component (1); this channel (33) ensures, when the igniter is armed, a passage for the gases between the two primary and secondary pyrotechnic charges of the igniter.
• the end of the primer holder part (4) opposite the end carrying the bore ( ⁇ réelle), carries a thread (20) on which is screwed a nut (6) which rests on a shoulder of the sliding part (4).
• a set of O-rings (8, 9 and 10) ensures the seal respectively between the primer holder part (4) and the outside of the igniter; between the sliding part (4) and the body (3) of the igniter; finally, between this sliding part (4) and the base (44) of the relay body (2) when the igniter is in the safety position (FIG. 1).
• the sliding primer holder (4) is hand held in the unarmed, that is to say safety, position, illustrated in FIG. 1.
• the channel (33) is closed by the part (4).
• the sliding part (4) immobilized by the stop (7) cannot slide and the channel (33) remaining closed, the gases emitted by the combustion of the primary pyrotechnic charge (5) are confined.
• the pyrotechnic chain being broken, the reinforcing relay (1) is protected and remains inert as well as the propellant.
• the retraction of the stop (7) being previously (or simultaneously) carried out elsewhere, it causes the ignition of the primer (5) by the electrical inlets ( 11).
• the pressure of the gases emitted can then cause the part (4) to slide.
• the igniter is in the armed position: the channel (33) is released; the gases pass through it and ignite the secondary pyrotechnic charge (1) which then plays its role and ignites the propellant.
• the invention applies to all types of igniters for propellant charges requiring a safety position capable of avoiding any risk of inadvertent ignition of the propellant charge.
• the igniter according to the invention thanks to the arrangement of the primer (5) and the relay (1) on the same axis (xy) and the arrangement of the primer (5) in the moving part ( 4), is particularly compact and simple to produce. Finally, the dead volumes being thus reduced to a minimum, it is possible to use a primer (5) containing relatively little pyrotechnic charge, leading to a relatively small production of gas, which lends itself to confinement and does not require exhaust to the outside in case of accidental ignition.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Air Bags (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9385245

Family Applications (1)

Country Status (3)

Cited By (3)

Families Citing this family (2)

Citations (5)

• 1989
  • 1989-09-08 FR FR8911747A patent/FR2651834A1/fr active Granted
• 1990
  • 1990-09-07 EP EP19900914191 patent/EP0443018A1/fr not_active Withdrawn
  • 1990-09-07 WO PCT/FR1990/000594 patent/WO1991003638A1/fr not_active Application Discontinuation

Patent Citations (5)

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