EP1013308A1 - Method and device for releasing pressure gas from an auxiliary cartridge particularly for fire fighting equipment - Google Patents

Abstract

The fire extinguisher, containing a solid or liquid extinguishing substance discharged by a propellant gas such as carbon dioxide, has a pyrotechnically-controlled perforator (6) to pierce a seal or disc (8) on the propellant gas cartridge (9). The perforator is actuated by a pyrotechnic cartridge (4). The fire extinguisher, containing a solid or liquid extinguishing substance discharged by a propellant gas such as carbon dioxide, has a pyrotechnically-controlled perforator (6) to pierce a seal or disc (8) on the propellant gas cartridge (9). The perforator is actuated by a pyrotechnic cartridge (4) delivering a sufficient quantity of gas into an expansion chamber (5) to enable it to pierce the seal or disc, and it is operated by a spring-loaded mechanical striker (1) held in the disarmed position by a removable pin (3).

Description

Subject of the invention

The present invention relates to a method and device which allow the release of a propellant enclosed in a sealed cartridge and intended in particular for an apparatus for combating fire such as a portable fire extinguisher.

Technological background

• les aérosols de fumées, lorsque la phase dispersée est solide,
• les aérosols de brouillard, lorsque la phase dispersée est liquide.

The operation of fire-fighting devices, in particular portable extinguishers, is based on the expansion to atmospheric pressure of two-phase dispersed systems kept pressurized in a hermetically sealed enclosure. These systems are distinguished according to the states of aggregation of the dispersing medium and of the dispersed phase, each of which can be solid, liquid or gaseous. The systems in which the dispersion medium is in the gaseous state are called aerosols, and are essentially of two types:

• smoke aerosols, when the dispersed phase is solid,
• mist aerosols, when the dispersed phase is liquid.

In the case of a powder extinguisher extinguishing, the latter constitutes the dispersed phase while the dispersion medium is a gas.

Relaxation at atmospheric pressure of a such dispersed pressurized system defines operation of a powder extinguisher and as such, it is assimilated to a smoke aerosol, the gas causing the powder when trigger, as defined by fire extinguishers included in the European standard and the EN3 standard.

Auxiliary pressure fire extinguishers are fire extinguishers in which the dispersion medium (gas) and the dispersed phase (extinguishing agent) are contained in separate tanks. Generally, the extinguishing agent in powder form is placed in the tank forming the extinguisher itself while the gas (CO ₂ or N ₂ ) is confined under high pressure in an auxiliary tank called an auxiliary gas cartridge. Depending on the case, these cartridges are placed in the extinguisher or outside the extinguisher. In such extinguishers, the diffusion of the dispersing gas in the extinguishing powder within the tank can only take place after the gas contained under high pressure in the auxiliary cartridge has been released.

State of the art

The auxiliary gas cartridges used in fire-fighting appliances, in especially portable fire extinguishers, are generally constituted by a metal tank in treated steel capable of withstanding strong fluctuations in internal pressure itself dependent on temperature (isochoric law). These auxiliary cartridges are hermetically sealed with a metal membrane calibrated called a seal or rupture disc.

Gas expansion in the cartridge auxiliary takes place when using the fire extinguisher as soon as the lid is pierced. Generally, the piercing of the cover is achieved by the use of a metal tip which can be of configuration and various shape, generally bevelled and / or tapered, and incorrectly called "striker" instead of "piercer operculum ". In the rest of this text, this point metal will be called "piercer" or "operculum piercer".

This piercer is adapted to be operated either directly (according to a system called "coup de fist "), either indirectly by manual action on force amplifying levers fitted with springs reminder. In such mechanical piercing systems, the section of the hole drilled in the cover remains reduced in because of the very design of the mechanisms used (stop and / or return spring systems) but mainly due to the effect obtained by the counter pressure developed at the time of the piercing of the cover when the gas in the auxiliary cartridge begins to expand to the fire extinguisher tank.

Aims of the invention

The present invention aims to provide a new process and a new device allowing the release of a propellant enclosed in a cartridge auxiliary used for example for a wrestling device against fire such as a portable fire extinguisher, which not have the disadvantages of state of the technical.

A particular object of the present invention aims to provide a method and a device comprising a lid piercer allowing optimal perforation of the seal of this auxiliary propellant cartridge which is used in or for a fire extinguisher, whatever the extinguishing agent or the charge of the extinguisher used.

Brief description of the figures

Figure 1

shows a sectional view of the device pyrotechnic perforation of the invention.

Figures 2a and 2b

represent a schematic view of a percussion pyrotechnic cartridge ring without primer (Figure 2a) and a pyrotechnic cartridge with central percussion with primer (Figure 2b) used in the device according to the present invention.

Figure 3

represents the comparative evolution of the pressurization of fire extinguisher tanks in the case of the use of a device manual for drilling the cover and in the case of the use of the device the invention.

Character-defining elements of the invention

The present invention relates to a method for releasing a propellant contained in a waterproof auxiliary cartridge intended in particular to be used in or for control devices fire such as fire extinguishers, in which one performs a perforation of an operculum or rupture disc of said auxiliary cartridge, characterized in that said perforation is obtained by the use of a means of pyrotechnic perforation.

Preferably, this perforation is carried out by the explosion of a pyrotechnic cartridge delivering in an expansion chamber a certain amount of gas whose pressure allows a piercer to perforate said cover (or rupture disc) of the auxiliary cartridge.

According to a preferred embodiment of the invention, the engagement of the perforation means pyrotechnic is carried out (possibly so manual) by moving a mechanical striker, projected towards said pyrotechnic cartridge so as to cause it to explode.

According to a first embodiment, the type of pyrotechnic cartridge allows annular percussion without primer.

According to another embodiment particularly preferred, the type of cartridge pyrotechnic allows a central percussion, preferably effected by the use of an auxiliary primer.

The present invention also relates to a device for releasing a contained propellant in a sealed auxiliary cartridge intended in particular for be used in or for control devices the fire, characterized in that it includes a means of pyrotechnic perforation of the cover (or disc of break) of the auxiliary cartridge.

Preferably, this means of perforation pyrotechnic includes a piercer associated with a cartridge pyrotechnics, the explosion of said cartridge pyrotechnic to generate a quantity of gas whose pressure is sufficient to generate the projection from said piercer towards the cover (or rupture disc) of the auxiliary cartridge and the perforation thereof.

Preferably, the piercer is presented under the shaped like a metallic point, usually shaped conical.

According to a first embodiment, the pyrotechnic cartridge does not include a primer.

According to another embodiment, the pyrotechnic cartridge includes a primer which allows to exert a central pressure on said cartridge pyrotechnic.

Advantageously, the device also includes training means presenting themselves for example in the form of an arming spring and stop or blockage occurring for example under the shape of a pin held by a safety system to move and / or stop the striker to the pyrotechnic cartridge.

The device also has holes regulator ensuring the depressurization of the gases caused by the explosion of the pyrotechnic cartridge.

A final aspect of the present invention relates to a fire-fighting device, in especially a portable fire extinguisher, comprising the device of the invention.

Detailed description of a preferred embodiment of the invention

Figure 1 shows a device for release of a propellant contained in a cartridge waterproof auxiliary which can be adapted to a fire fighting, especially a fire extinguisher portable with the general reference 12. The cartridge auxiliary may be integrated into the extinguisher or be outside of it.

The device of the invention comprises as a piercer (or piercer for a seal) a conical metal tip 6 set in the rest position, which closes expansion orifices 7 and faces the metal seal 8 of an auxiliary gas cartridge 9 (for example a CO ₂ or N ₂ gas cartridge).

The device of the invention comprises a pyrotechnic cartridge 4 including explosion in a chamber expansion 5 allows the release of a certain amount of gas, the increasing pressure of which reaches a certain value that will propel the piercer 6 towards the cover 8 (movement of the piercer 6 and drilling of cover 8).

During its stroke, the piercer 6 will release the expansion ports 7, causing depressurization in the expansion chamber 5, while the piercer 6 continues its inertial travel towards the inside of the cartridge gas auxiliary 9 after drilling the cover 8.

As soon as the piercer 6 has fully penetrated in the auxiliary cartridge 9 thanks to the opening practiced in cover 8, the gas confined under high pressure relaxes polytropically by through the openings 7 completely cleared then that simultaneously, the piercer 6 sees its speed decrease under the action of the gaseous backflow of expansion opposite to its path. Therefore, after the perforation, the piercer 6 is found in the auxiliary gas cartridge 9.

During the relaxation period, the relaxed gas released (dispersing medium) is channeled down the fire extinguisher tank containing the extinguishing agent (dispersed phase).

It diffuses there with a diffusion coefficient dependent on the average speed of its molecules, for form, after backwashing and mixing, a dispersed system two pressurized phases.

Advantageously, the engagement of the pyrotechnic cartridge 4 can be carried out without primer (from manually) using a striker 1 held in a so-called high position and armed by an arming spring or any other means capable of ensuring movement from said striker to the pyrotechnic cartridge 4. A arming spring allows, by its relaxation, to drive the striker 1 when the pin 3 is removed after breaking of the security system 2 holding said pin. Of advantageously, the security system 2 comprises a classic metal pin that can be sealed.

Advantageously, the release device gas trapped in the auxiliary cartridge allows a optimal and particularly rapid perforation of the cover present on said cartridge.

We observe that we can use in the device and method according to the present invention both pyrotechnic cartridges with annular percussion without primer (Figure 2a) as pyrotechnic cartridges to central percussion, i.e. cartridges pyrotechnics with primer 20 (Figure 2b).

The present invention can be applied to particularly advantageous to all electric firing in pyrotechnic cartridges.

This type of device and method can be used for auxiliary cartridges used in or even outside of fighting devices fire, and in particular portable fire extinguishers.

We also observe that this type of process and device can be applied to all types of auxiliary gas cartridge, whatever the phase diffusing, and is valid for all models fire extinguisher whose capacity varies from a few kilos to a few tens of kilos.

Finally, we observe that the present invention can be applied to all types of agent fire extinguisher (diffused phase).

For example, the data below are specific to the pyrotechnic perforation of auxiliary propellant cartridges for fire extinguishers portable powder with a load of 9 kg.

Auxiliary gas cartridge

Type of gas: carbon dioxide (CO ₂ ) Filling density: 0.73 kg / l Cartridge material: Special steel ST 52.4 NBK Bursting pressure of the cylinder: 600 bars Gas purity: 99.5% Lid thickness: 0.25mm Material of the cover: copper alloy Diameter of the cover: 6 mm Burst pressure: 490 bars CO ₂ vapor pressure: at -20 ° C = 20 bars at +60 ° C = 225 bars

Pyrotechnic perforator

The experimental setup is similar to that of FIG. 1. A pressure tap was installed directly at the level of the expansion chamber 5. Material : treated steel Maximum diameter: 5 mm Maximum length: 18 mm Cone angle: 30 ° Volume of the expansion chamber: 1327 mm ³ Conditioning of CO ₂ auxiliary cartridges: 24 h at +75 ° C CO ₂ vapor pressure at +75 ° C: 310 bars Measuring device : Kistler 601H piezo sensor

Table 1 below gives the maximum pressure values in the expansion chamber. Pressure measurement in the expansion chamber Experience number Maximum pressure (bar) 1 CO2.034 731 2 CO2.035 737 3 CO2.036 752 4 CO2.038 759 5 CO2.039 669 6 CO2.040 674 7 CO2.041 711 8 CO2.042 790 9 CO2.043 780 10 CO2.044 806

The value of the average drilling pressure is 730 bars.

The tables below give the results of measurements carried out on auxiliary CO ₂ gas cartridges intended for portable powder extinguishers with a load of 9 kg. They make it possible to calculate in each case the quantity of CO ₂ in solid phase (dry ice) resulting after each expansion at atmospheric pressure. The filling density of the cartridges is in accordance with European standards EN3 and is in particular less than 75%, the weight of the quantity of CO ₂ gas is 150 grams, the filling filling tolerance of +/- 5 g being neglected in the results.

The evolution of the total weight of the cartridges auxiliaries during expansion was carried out by method continuous weighing.

Comparative analysis of a manual drilling of the lids by compared to a pyrotechnic perforation Manual drilling of the lids

Weight of auxiliary cartridges before drilling 578 gr Hole diameters 1.5mm CO ₂ expansion section 1.8 mm ² Total duration of relaxation 60 sec Amount of solid CO ₂ +/- 22 gr Evolution of the total weight of the cartridges auxiliaries T = 0 + 5 sec + 30 sec + 60 sec + 20 ° C 578 g 512 g 475 g 451 g - 25 ° C 578 g 535 g 477 g 450 g

Pyrotechnic drilling of the lids

Weight of auxiliary cartridges before drilling 567 gr Hole diameters 5 mm CO ₂ expansion section 20 mm ² Total duration of relaxation 2 sec Amount of solid CO ₂ +/- 7 gr Evolution of the total weight of the cartridges auxiliaries T = 0 + 5 sec + 30 sec + 60 sec + 20 ° C 567 g 427 g 425 g 424 g - 25 ° C 567 g 429 g 427 g 426 g

The results of Tables 2 and 3 show that whatever the temperatures of use of the process of perforating the lids of auxiliary gas cartridges, the rate of production of CO ₂ in solid phase (dry ice) is always less than +/- 30 % compared to the traditional manual piercing system for lids.

In addition, regardless of the reduction in dry ice content, pyrotechnic perforation of lids promotes, by the perforated section, the reduction in the time required to pressurize the fire extinguishers as shown in Figure 3.

Claims (11)

Method for releasing a propellant contained in a sealed enclosure such as a cartridge auxiliary intended in particular to be used in a fire-fighting device in which performs a perforation of a rupture disc or disc (8) of said auxiliary cartridge (9), characterized in that that said perforation is obtained by the use of a means of pyrotechnic perforation. Method according to claim 1, characterized in that said perforation is carried out by the explosion of a pyrotechnic cartridge (4) delivering in an expansion chamber (5) a sufficient amount of gas whose pressure allows a piercer (6) to perforate the seal or rupture disc (8) of the cartridge auxiliary (9). Method according to claim 2, characterized in that the explosion of the cartridge pyrotechnic (4) is caused by the movement of a mechanical striker (1) projected towards said cartridge pyrotechnic (4) so as to cause it to explode. Gas release device propellant contained in a sealed auxiliary cartridge intended in particular to be used in or for fire fighting apparatus, characterized in that it comprises a pyrotechnic perforation means (4) of the seal (8) or rupture disc of the cartridge auxiliary (9). Device according to claim 4, characterized in that the perforation means comprises a pyrotechnic cartridge (4) whose explosion in a expansion chamber (5) allows the release of a quantity sufficient gas whose pressure allows projection a piercer (6) towards the cover (8). Device according to claim 5, characterized in that the explosion of the cartridge pyrotechnic (4) is caused by the movement of a mechanical striker (1) capable of being projected towards this pyrotechnic cartridge (4). Device according to claim 6, characterized in that the striker (1) comprises means drive such as an arming spring and means blocking device such as a pin (3) held by a metal spindle respectively ensuring movement and blocking the striker (1). Device according to any one of Claims 4 to 6, characterized in that the cartridge pyrotechnic (4) comprises a central primer (20). Device according to any one of Claims 4 to 6, characterized in that the cartridge pyrotechnic (4) does not include a primer. Fire fighting device comprising the device according to any one of claims 4 to 7. Fire fighting device according to claim 8, having an auxiliary cartridge (9) internal or external to the fire extinguisher.

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