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EP0456484A1 - Dispositif sensible à la température - Google Patents

Dispositif sensible à la température Download PDF

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Publication number
EP0456484A1
EP0456484A1 EP91304158A EP91304158A EP0456484A1 EP 0456484 A1 EP0456484 A1 EP 0456484A1 EP 91304158 A EP91304158 A EP 91304158A EP 91304158 A EP91304158 A EP 91304158A EP 0456484 A1 EP0456484 A1 EP 0456484A1
Authority
EP
European Patent Office
Prior art keywords
firing
initiator
actuator
volatile liquid
container
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91304158A
Other languages
German (de)
English (en)
Inventor
John Dudley Lewis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems Electronics Ltd
Original Assignee
GEC Marconi Ltd
Marconi Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GEC Marconi Ltd, Marconi Co Ltd filed Critical GEC Marconi Ltd
Publication of EP0456484A1 publication Critical patent/EP0456484A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • F42C15/36—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges wherein arming is effected by combustion or fusion of an element; Arming methods using temperature gradients

Definitions

  • the present invention relates to a temperature sensitive device which acts when the ambient temperature exceeds a predetermined level.
  • Such temperature sensitive devices are found in what are known as "Temperature Sensitive Pyrotechnical Train Interruption Devices" such as are described in US4709637. These devices operate at higher temperatures than would normally be encountered, such as those in a fire, and serve to destroy munitions such as missiles so as to prevent thermal explosion or initiation of an explosive firing train.
  • a significant part of such devices is the mechanism to arrange for firing of the interruption device at a predetermined temperature, and devices utilising low melting eutectic alloys have been proposed.
  • the previously proposed firing devices comprise a spring loaded plunger having a firing pin thereon and held against the spring by one or more retaining members made from a eutectic alloy. When a given temperature is exceeded, the alloys melt so allowing the spring to drive the plunger against the detonator.
  • the present invention has arisen in an attempt to provide a firing device which is not stressed until the ambient temperature approaches the operational temperature and in which the possibility of accidental firing is reduced.
  • a temperature sensitive firing device comprising: a container of a volatile liquid; an actuator held in position by releasable securing means; an initiator; and a firing arrangement, the device being such that, above a threshold temperature, expansion of the volatile liquid causes the actuator to move whereby the initiator initiates the firing arrangement.
  • the problems associated with previously known temperature sensitive devices are reduced or eliminated because the device includes no stressed components during normal temperature conditions. Stresses are only introduced when the ambient temperature rises and the device reaches its operating temperature.
  • the container may be, for example, of a bellow construction of a snap-action type in which a rapid change in volume occurs when the temperature threshold is exceeded.
  • the container is frangible.
  • the container is arranged to fracture as the internal pressure of the liquid increases when the temperature rises beyond a certain level.
  • the actuator is a piston mounted in a cylinder which also contains the container.
  • the actuator could be some other form of coupling to transmit to the firing arrangement the impulse caused by expansion of the volatile liquid.
  • the firing arrangement is a detonator and the initiator is a firing pin.
  • the firing arrangement could be a trip mechanism, for example, involving a train of latches.
  • the initiator be mounted on the actuator. However, it could be positioned separately from the actuator or mounted on the firing arrangement. The initiator could form an integral part of the actuator or be a separate member fixed to move with it.
  • the initiator is spaced from the firing arrangement by a fusible member, and advantageously the fusible member is a collar which preferably is formed from eutectic alloy.
  • the fusible member is a collar which preferably is formed from eutectic alloy.
  • the releasable securing means is conveniently a shear pin or detent. However, it could be formed simply as a push fit between the actuator and a housing.
  • the releasable securing means is arranged to release the actuator once the pressure due to the action of heat upon the volatile liquid has reached a given level.
  • the fusible member is arranged to melt before the securing means is released.
  • these actions could be reversed or be arranged to be substantially simultaneous.
  • the liquid is typically ethyl chloride and is arranged to give a pressure of about 20 atmospheres at the required temperature, in this case about 127°C. Obviously, other liquids can be chosen to give the required pressure at other temperatures.
  • the device comprises a body 10 defining a cylinder 12 therein.
  • a slidable piston 14 is mounted within the cylinder 12 and is retained in position by a shear pin 16.
  • a thin walled, frangible container 18 of ethyl chloride or the like is positioned within the cylinder 12.
  • the piston 14 has a firing pin 20 projecting axially therefrom towards a detonator 22 mounted in the wall of the body 10 opposite said piston.
  • a collar 24 is interposed between said piston 14 and the detonator 22 so as to prevent the firing pin 20 from contacting the detonator.
  • a vent passage 26 is provided in the body 10 to communicate with the outside thereof.
  • the device described above can form part of a pyrotechnical train interruption device similar to that described in US4709637.
  • the collar 24 which is formed from a eutectic alloy melts, the molten alloy draining from the vent 26.
  • the container 18 fractures due to the pressure of the ethyl chloride and the pressure within the cylinder 12 builds up until the pin 16 shears and allows the piston 14 to driven down such that the firing pin 20 strikes the detonator 22.
  • the invention described has the advantage that its components do not become stressed until the container 18 fractures so reducing any problems of fatigue or due to physical damage or errors in production.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Bags (AREA)
  • Fuses (AREA)
EP91304158A 1990-05-11 1991-05-09 Dispositif sensible à la température Withdrawn EP0456484A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB909010565A GB9010565D0 (en) 1990-05-11 1990-05-11 Temperature sensitive device
GB9010565 1990-05-11

Publications (1)

Publication Number Publication Date
EP0456484A1 true EP0456484A1 (fr) 1991-11-13

Family

ID=10675809

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91304158A Withdrawn EP0456484A1 (fr) 1990-05-11 1991-05-09 Dispositif sensible à la température

Country Status (2)

Country Link
EP (1) EP0456484A1 (fr)
GB (2) GB9010565D0 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11371623B2 (en) 2019-09-18 2022-06-28 Saudi Arabian Oil Company Mechanisms and methods for closure of a flow control device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2843042A (en) * 1951-08-04 1958-07-15 Montedison Spa Non-metallic mine fuse
US4709637A (en) * 1984-05-25 1987-12-01 Matra Temperature sensitive pyrotechnical train interruption device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL92497C (fr) * 1951-08-04
US3854401A (en) * 1967-12-01 1974-12-17 Us Army Thermal ignition device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2843042A (en) * 1951-08-04 1958-07-15 Montedison Spa Non-metallic mine fuse
US4709637A (en) * 1984-05-25 1987-12-01 Matra Temperature sensitive pyrotechnical train interruption device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11371623B2 (en) 2019-09-18 2022-06-28 Saudi Arabian Oil Company Mechanisms and methods for closure of a flow control device

Also Published As

Publication number Publication date
GB2245347A (en) 1992-01-02
GB2245347B (en) 1993-09-15
GB9010565D0 (en) 1990-10-17
GB9109642D0 (en) 1991-07-17

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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