RU2816730C1 - Electric pyro cartridge based on diode laser - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of ignition of powder and pyrotechnic charges, which are actuated by means of optical means, and namely to a laser pyro cartridge. Electric pyro cartridge based on a laser diode comprises a housing, an igniting charge located inside the housing and limited by a protective cover, an insulator and electric contacts. In the insulator there is a laser diode. Charge ignition initiator is a laser beam. Through window is made in the pyro cartridge housing to direct the laser beam. Laser beam is directed by means of a quartz glass fiber light guide passing from the laser diode through the through window.

EFFECT: creation of a reliable unified device for ignition of charges.

1 cl, 2 dwg

Description

The invention relates to the field of ignition of powder and pyrotechnic charges actuated by optical means.

An electric squib is known, which includes a housing, an ignition charge located inside the housing and closed with a lid, an insulator, electrical contacts, an incandescent bridge inside the charge (Fakhrutdinov I.Kh., Kotelnikov A.V. Design and design of solid fuel rocket engines. M. Mechanical Engineering, 1987 - 328 pp. ill., p. 209).

The operating principle of the squib is as follows. Electric current is supplied to two contacts of the electrical connector, between which there is an incandescent bridge, for example, made of 0.02...0.04 mm nichrome wire. Under the influence of heat from a heated incandescent bridge, the igniter charge, which can consist of one, two or three components, ignites. In the device under consideration, the ignition charge consists of an initiating mixture located around the filament bridge, a transfer composition and the main composition of the mixture.

The high-temperature combustion products formed when the charge is ignited are used to ignite various pyrotechnic and ignition devices, as well as as a source of pressure when various automatic mechanisms are triggered.

The disadvantages of this electric squib include the following:

1. Complexity of manufacture and high cost.

2. The possibility of unpredictable operation of the squib under the influence of a discharge of static electricity that occurs on a technical device, as well as under the influence of electromagnetic induction, leading to the emergence of an electric current in the incandescent bridge and ignition of the pyrotechnic charge.

3. To prevent the ignition of powder and pyrotechnic charges as a result of unpredictable operation of the squib, there is a need to use complex mechanical safety devices (Auxiliary systems of rocket and space technology. Translation from English. M. "Mir", 1970, pp. 185...215).

Known electric ignition devices: patent RU 2180724, published 03/20/2002; patent RU 2196954 dated January 20, 2003; patent RU 2401412, published 10.10.2010; patent RU 2527985, published on September 10, 2014, in which attempts are made to protect electric igniter devices from the discharge of static electricity, which on some products can reach 1000-1500 V. The above devices are extremely complex and provide only partial protection against operation of the electric igniter device (squib) when the occurrence and accumulation of static electricity on the product.

There is a well-known patent RU 2196292, published on 10/01/2003, which proposes a design to avoid unwanted activation of an electric igniter (squib) from an electric current in an incandescent bridge as a result of electromagnetic induction, for example, under the influence of high-frequency radiation. However, this device is extremely complex and does not protect against static electricity discharge.

There is a known patent RU 2642764 C2, published on 08.08.2018, “Solid propellant rocket engine (variants)”, in which the ignition device or the solid fuel itself is ignited using an intense laser beam. The main objective of the invention is to increase the reliability of solid fuel ignition and reduce the likelihood of spontaneous engine starting. The disadvantage of this invention is the long time it takes for the engine to reach a stable operating mode due to the low initial pressure in the combustion chamber of the solid propellant rocket engine, which makes it impossible to use it in solid propellant rocket engines with a large free volume. Also, as a disadvantage of the technical solutions proposed in the patent, it should be noted that they require the development of an original separate ignition system each time.

The main goal of the proposed invention is to create a reliable unified (standardized) ignition device for wide application. As a prototype, we will choose an electric squib described at the very beginning of the application for an invention from the book by Fakhrutdinov I.Kh., Kotelnikov A.V. on page 209.

The diagram of the proposed device is shown in Fig. 1. The electric squib includes: body 1, ignition charge 2, protective cover 3, insulator 6, back cover 7, electrical contacts 8. The main difference from the prototype is that instead of an incandescent bridge, a laser diode beam is used to ignite or ignite the charge 5, to which electrical contacts 8 are connected. To direct the laser beam to the ignition charge, a window 4 (hole) is provided in the squib body. The window can be made through or glazed, for example, quartz glass. When electric current is applied to the contacts of a laser diode, it generates a light beam that focuses on the surface of the charge and ignites it. The resulting combustion products of the charge knock out the protective cover and activate the ignition device (igniter), or some kind of locking or other mechanism.

The authors of the application tested laser diodes of various light powers. Thus, a 4 W laser diode with a focal spot diameter of 1 mm ignited a charge of condensed high-energy matter in 0.02 s. The intensity of the radiant heat flux to the substance was 5.1×10 ³ kW/m ² .

The process of igniting the charge included preheating the surface of the charge, ignition and reaching a stationary combustion mode. When using black powder as a charge, the ignition process occurred almost instantly. Experiments have shown that when using a laser diode as an ignition initiator, there is no need to use initiating and transfer charges; a metallized high-energy substance can be ignited directly.

The authors of the application carried out similar tests with a laser diode having a fiber output. In this laser, the light beam exits through the quartz glass fiber 9 through the window 4, as shown in FIG. 2. The use of this light guide improves the design of the electric squib, since such a laser has a higher efficiency compared to a conventional one. In the experiment, a laser with a quartz light guide with a diameter of 0.105 mm was used. The laser light power varied within 1…10 W. Experiments have shown that the small diameter of the light guide makes it possible to obtain the necessary heat flux to the substance with a relatively low power of the laser diode.

Depending on the weight of the powder charge, as well as the type of fuel in the sample, it is possible to use either a laser beam or a light guide, which allows for the most complete combustion of the fuel in the sample and minimizes the time it takes for the engine to reach operating mode.

Claims (1)

An electric squib based on a laser diode, containing a housing, an ignition charge located inside the housing and limited by a protective cover, an insulator, electrical contacts, characterized in that a laser diode is located in the insulator, the initiator of ignition of the charge is a laser beam, and for directing the laser beam in the housing The squib has a through window, and the laser beam is directed through a quartz fiberglass light guide passing from the laser diode through the through window.

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