BE1019460A3 - FIRE EXTINGUISHER VALVE HEAD AND USE THEREOF. - Google Patents

Abstract

The present invention relates to a valve head for an extinguisher characterized in that it comprises a valve body comprising a central channel intended to receive a rod, and a lateral channel constituting a channel for draining an extinguishing agent, a control lever. connected to said valve body by journals, and a safety cam mounted removably and slidably on top of the valve body, completely covering said control lever, said cam being formed in one piece and having on a front face a seal forming an integral part of said part, said safety cam comprising an upper wall provided at its center with a sliding ramp located on the lower face of said upper wall said sliding ramp allowing the lever to tilt during the traction of the safety cam.

Description

Fire extinguisher valve head and its use Technical field of the invention

The present invention relates to an auxiliary pressure fire extinguisher valve head and its use on a fire extinguisher body and its use for the extinguishing of a fire.

Technological background of the invention

A fire extinguisher contains an extinguishing agent capable of extinguishing flames, which can be projected on a fire by the action of internal pressure. This pressure can be provided by a permanent pre-pressure (permanent pressure system) or by the release of an auxiliary gas (very often carbon dioxide) contained in a cartridge (auxiliary pressure system).

Known auxiliary pressure extinguishers consist essentially of an enclosed tank (body) having an upper wall which has an opening whose contour has a generally circular shape, a generally cylindrical tube assembly, and a head (valve ) fire extinguisher. These three elements, namely the reservoir, the plunger assembly and the extinguisher head are usually assembled by engaging the upper portion of the plunger assembly internally provided with a female thread into the opening of the plunger tube assembly. the upper wall of the tank, and then screwing into the female thread of the tube assembly the extinguisher head which has for this purpose a cylindrical lower portion externally provided with a male thread.

The body of the extinguisher is usually intended to contain the extinguishing agent. The plunger tube assembly usually contains a compressed gas cartridge adapted to propel the extinguishing agent into the body through passages formed in the plunger tube assembly and the extinguisher head, and to project said extinguishing agent towards flames to extinguish, through an exit port of the extinguisher head, when the fire extinguisher is activated.

Activation of the fire extinguisher is usually carried out by operating an operating lever pivotally mounted on the extinguisher head. When this lever is actuated, it acts on an element that pushes the compressed gas cartridge on a perforator that perforates the cartridge to release the gas and cause the expulsion of the extinguishing agent. This operation is made possible only if a locking pin of said presser lever has been previously pulled.

The implementation of these fire extinguishers was not always easy, especially when the user is in a feverish situation in case of fire. Indeed, the tearing of the safety pin which passes through the pressure lever, requires, because of the shear effect, a certain strength and is not very easy because the device can be maintained inclined and n is not at the user's hand. It is then necessary to exert a pressure also strong enough to maneuver the lever to activate the extinguisher which is more difficult if the tank is not in support on the ground. Known fire extinguishers also have a number of other disadvantages, such as the fragility of the non-impact-protected fire extinguisher head.

The present invention aims to solve at least one of these problems. In particular, the object of the present invention is to improve the operation of a fire extinguisher valve head, preferably an auxiliary pressure extinguisher. In particular, the invention aims to improve the operation of a fire extinguisher head by optimizing the percussion system (perforation) of the propellant cartridge.

Summary of the invention

In a first aspect, the invention relates to a fire extinguisher head (also named after valve head) for fire extinguishing apparatus, and preferably for auxiliary pressure fire extinguisher.

The present invention relates in particular to a fire extinguisher head characterized in that it comprises: a valve body comprising (mainly) a central channel (bore) for receiving a rod, and a lateral channel (boring) (perpendicular to the central channel ) constituting a drain channel of an extinguishing agent, a control lever connected to said valve body by journals, and a safety cam removably and slidably mounted on top / top of the valve body, completely covering said lever control device, said cam being formed in one piece and having on a front face (or front wall) a seal integral with said workpiece and which can be torn off when the safety cam is extracted, said cam security comprising an upper wall (face) provided at its center with a sliding ramp located on the lower face of said upper wall, said r sliding arm for tilting the lever when pulling the safety cam.

The present invention has the advantage of reducing the pulling force of the safety cam (or cap) in order to facilitate percussion by the user and to improve the values imposed by the EN3 - 6/7 standard (applicable for Portable fire extinguishers).

The present invention has the advantage of giving more comfort to the user by allowing it to be put into operation either by a finger or by the hand (take trigger type colt).

The present invention has the advantage of completely protecting and covering the lever from any accidental operation.

The present invention also has the advantage of increasing the effectiveness of the seal.

The present invention also has the advantage of reducing the volume of the head or valve extinguisher.

The present invention also has the advantage of reducing the parasitic noise of the head or valve of the extinguisher placed in moving vehicles.

The present invention also has the advantage of reducing the number of parts of the head or valve extinguisher to reduce production costs and assembly.

It is also important, especially for safety reasons, that the service or maintenance personnel of the fire extinguishers can check in a very simple and quick way if the extinguisher has already been used, with this extinguisher head, this problem is solved by the fact that the tamperproof seal is an integral part of the safety cam.

According to a particular embodiment, the valve head is characterized in that the top or top of the valve body is provided with longitudinal grooves (on two lateral parts of said body) located on either side of the control lever (perpendicularly to the axis of rotation of the control lever), the grooves serving as a slideway to said safety cam

According to a particular embodiment, the valve head is characterized in that the longitudinal portions of the base of the safety cam are shaped in the form of rails provided for sliding of the safety cam in the grooves of the valve body.

According to a particular embodiment, the valve head is characterized in that the part of the safety cam opposite to the outlet passage of the extinguishing agent is provided with an opening acting as a catch for the traction of the cam of security (eg allowing the passage of at least one finger).

According to a particular embodiment, the valve head is characterized in that the valve body comprises on the top of its front face a housing (or groove) capable of receiving the lower portion of the seal of the safety cam.

According to a particular embodiment, the valve head is characterized in that the valve body comprises on the part opposite the emptying channel an opening (for example to allow the passage of at least one finger) acting as maintaining the fire extinguisher.

According to a particular embodiment, the valve head is characterized in that the safety cam comprises two side walls on either side of the upper wall, said side walls and upper having an arrow indicating the direction of traction.

In another aspect, the invention also relates to the use or application of a valve head according to the present invention for an extinguisher, preferably for an auxiliary pressure extinguisher.

The invention also relates to a fire extinguisher apparatus comprising a fire extinguisher head according to the present invention.

According to a particular embodiment, the apparatus comprises a body containing a extinguishing agent of the extinguishing powder type, and a central tube, provided inside said body, in which is placed a pressure cartridge containing a propellant gas.

According to a particular embodiment, the apparatus is characterized in that said extinguisher head comprises: a valve body mainly comprising a central channel (bore) intended to receive a rod, and a lateral channel (boring) (perpendicular to the central channel) constituting a drain channel of the extinguishing agent, a rod mounted in said central channel of the valve body, and controlling the opening and closing of said drain channel, an upper centering device for centering said rod screw a control lever connected to said valve body with trunnions, and a safety cam removably and slidably mounted on the top / top of the valve body, completely covering said control lever, said cam being formed in one piece and having on one face (wall) before a seal forming an integral part of said part and which can be torn off when the safety cam is extracted, said safety cam comprising an upper wall (face) provided at its center with a sliding ramp located on the lower face of said upper wall, said sliding ramp allowing the lever to tilt during the traction of the safety cam.

According to a particular embodiment, the apparatus is characterized in that said upper centralizer is composed of a cylindrical chamber at the base of which is mounted a holding ring containing openings for the passage of the extinguishing agent.

According to a particular embodiment, the apparatus is characterized in that said rod comprises: - a return spring bearing on said retaining ring of the upper centering device, an upper seal ensuring the sealing of the central channel beyond the channel drain, a central seal sealing the front of the drain channel, and a lower seal ensuring the sealing of the chamber of the upper centering.

According to a particular embodiment, the apparatus is characterized in that said body comprises a lower centralizer, provided inside said tube, provided with one or more diffusers passing through the transverse wall of said tube and for expelling the gas propellant contained in said cartridge directly in the extinguishing agent. The apparatus may comprise one or more diffusers passing through the transverse wall of said tube, for example at least 1 diffuser, at least 2, at least 3 or at least 4 diffusers or more. Preferably the apparatus comprises 1 or 2, or 3, or 4 diffusers, more preferably 2 diffusers.

According to a particular embodiment, the apparatus is characterized in that the end (s) of the at least one diffuser are housed in one or more cells formed by a deflector (s) located on the outer wall of said tube.

According to one embodiment, the apparatus is characterized in that the cartridge is essentially cylindrical and provided with a neck containing a cover provided for the perforation of the cartridge. Preferably, the apparatus is characterized in that the cartridge is placed upside down in said central tube with its neck and its lid oriented towards the base of the body.

According to a particular embodiment, the apparatus is characterized in that the central tube is divided into an upper part and a lower part whose outer diameter is smaller than the outer diameter of the upper part of said tube. Preferably, the cartridge is mounted within the upper portion of said central tube, and the outer diameter of said cartridge is smaller than the inner diameter of said upper portion of the tube, so that a circumferential gap is created between said cartridge and the upper part of said tube. In addition, in another particular embodiment, the apparatus is characterized in that said lower centralizer is provided in the upper part of said central tube at the neck of said cartridge.

The one or more diffusers of the propellant gas may be provided at a height between the lower half height and the third lower quarter of the internal height of said body. Preferably, the one or more diffusers are directed downwards and pass from the inside of the central tube towards the heart of the mass of powder.

According to a particularly preferred embodiment, said lower centralizer is composed of a cylindrical chamber containing a piston assembly which is mounted, preferably by clipping, on the cartridge. Preferably, said piston assembly comprises: a piston, a seal ensuring the sealing of the propellant gas during the perforation of the cartridge between said piston and said cartridge at the neck of the cartridge, a seal ensuring the sealing of the propellant gas during the perforation of the cartridge between the outer diameter of said piston and the inner diameter of said lower locator, a striker placed in the center of the piston resting on the bottom of said lower centralizer for perforating the cartridge at the seal of said cartridge, and a lower spring (holding) placed in the center of the piston bearing on the bottom of said lower center, for controlling the position of the piston assembly.

According to another aspect, the invention relates to a fire extinguishing process in which preferably an extinguisher apparatus according to the invention is implemented.

The present fire extinguishing method using an extinguisher apparatus comprising a body containing a fire extinguishing powder extinguishing agent, a fire extinguisher valve head according to the invention attached to said body and a central tube provided therein body, in which is placed a pressure cartridge containing a propellant, said method comprising a pressurization of the extinguisher and the emptying of the extinguishing agent, is preferably characterized in that the pressurization comprises the following steps of: traction by sliding of the safety cam of the extinguisher valve head, breaking of the seal during the pulling of said safety cam, tilting of the lever of the extinguisher valve, percussion of said cartridge for releasing the propellant contained in said cartridge directly into the extinguishing agent, and transporting the mixture of propellant and extinguishing agent to the extinguisher head.

According to one embodiment of said method, the pressurization of said extinguisher and the emptying of the extinguishing agent are carried out simultaneously. According to another embodiment, the pressurization of said extinguisher and the emptying of the extinguishing agent are carried out consecutively.

Other features and advantages of the present invention will appear on reading the description which follows with reference to the accompanying drawings.

Brief description of the drawings

Figure 1 shows a schematic sectional view in the plane of symmetry of a fire extinguisher apparatus according to a particular embodiment of the invention before use.

Fig. 2 shows the extinguisher apparatus of Fig. 1, in which the seal of the safety cam is broken.

FIG. 3 represents the extinguishing apparatus of FIG. 1, in which the safety cam is removed, causing the lever of the extinguisher head to tilt and thus the percussion of the cartridge thus releasing the propellant gas into the body the homogenization of the propellant and extinguishing agent is carried out in the body of the apparatus.

Figure 4 shows the extinguisher apparatus of Figure 1, wherein the homogenization of the propellant and the extinguishing agent is in the body of the apparatus, putting the apparatus under pressure.

Figure 5 shows the emptying of the extinguisher apparatus of Figure 1, by actuating the lever of the extinguisher head.

detailed description

An auxiliary pressure type fire extinguisher generally consists of a body, preferably a metal cylinder, a valve (also known as a fire extinguisher head, valve head, or shut-off valve), a central tube, and a propellant cartridge. Portable fire extinguishers are equipped with a handle to carry the fire extinguisher and to strike the cartridge. According to the present invention the term "extinguisher" is synonymous with the term "fire extinguisher".

The present invention aims to improve the operation of the fire extinguisher valves by optimizing the percussion system (perforation) of the propellant cartridge.

According to the present invention the term "fire extinguisher valve" is synonymous with "fire extinguisher head", or "valve head" or "fire extinguisher shutoff valve".

The extinguisher valve head has been improved by providing a one-piece safety cam in which a slip ramp is formed, and which includes a tamper-evident seal integral with the safety cam.

According to the present invention, the term "safety cam" is synonymous with "security cache" or "security cap".

According to the present invention, the percussion of the cartridge is carried out by simple pulling on the safety cam. During this traction, the sliding ramp of the safety cam pivots the lever of the valve body about its axis and simultaneously, by this same action, breaks the seal. When pivoting the lever, the action on the rod (drawer) contained in the valve body induces the perforation of the cartridge. This perforation releases the propellant gas into the bottle.

Referring to Figure 1, an extinguisher 2 according to a particular embodiment of the present invention is illustrated. Figures 2, 3 and 4, and 5 show schematically the operation of an apparatus 2 according to a particular embodiment of the present invention.

According to a particular embodiment of the invention, the basic elements of extinguisher 2 comprise: a bottle 17, also called "body" in the present invention, which bottle is a container or tank, generally cylindrical, made of metal or made of plastic, intended to be pressurized internally and provided with the welded parts.

- A valve head 1 also called "stopcock" or "extinguisher head" in the present invention, which fulfills several functions. Initially it serves as a closure cap of the bottle 17. Then it allows the perforation of the cartridge 20 of propellant 21. Finally, it allows the extinguishing agent 18 to be emptied at one time or intermittently.

an extinguishing agent 18, which is an assembly of the product or products contained in extinguisher 2 and whose action causes extinction. The nature of the extinguishing agent used depends on the most likely fire class in the area of use of the appliance. There are different classes of fires, including fires of solid materials (class A); liquid materials or liquifiable solids (class B), gases (class C), metals (class D). The main extinguishing agents that can be used in the present invention are as follows. In parentheses, the classes on which they can be used: water spray (A); water spray with additive (emulsifier) (AB); powders ABC (ABC); BC (BC) powders; carbon dioxide (BC) or powders D (D). Preferably, the extinguishing agent is an ABC type powder.

a cartridge 20, which comprises a metal container under pressure containing a propellant 21, for example CO 2. The neck 32 of the cartridge 20 contains the seal 33 provided for perforation - a striker 34 preferably made of steel, it can be hollow and split along its entire length and is used for perforating the propellant cartridge 20. One end is beveled to facilitate perforation.

a central tube 19 for driving the mixture of the extinguishing agent 18 and the propellant 21 to the head of the apparatus 1 and thus to the outside.

The upper part of the apparatus, that is to say the elements of the valve head 1 according to a particular embodiment of the invention is described below.

The valve head 1 is composed of the valve body 3 comprising a control lever 7, a spool or rod 5 and an upper centering device 22. This assembly is covered with a safety cap or cam 9 in which a seal 11 is incorporated. .

The valve body 3 is designed to receive all the elements making up the valve 1. The valve body 3 mainly comprises a central channel (bore) 4 intended to receive the rod (or slide) 5 and the upper centering device 22, and another channel (bore) 6 generally perpendicular to the first for the outlet passage of the extinguishing agent 18. This channel 6 is also called drain channel or outlet channel 6 of the extinguishing agent. The valve body 3, in this case, is fixed to the bottle 17 by screwing and the sealing of these two parts is provided by an o-ring type head gasket 35.

Two holes 36 located on either side of the lateral parts of the valve body 3 are intended to receive the journals 8 of a control lever 7.

At the top of the valve body 3 is formed a longitudinal groove on each lateral portion serving as slideway 55 to the safety cap or cam 9.

A housing 15 at the top of the front face of the valve body 3 is provided to receive the lower part of the seal 11.

On the rear part of the valve body 3, opposite the outlet channel 6 of the extinguishing agent, is an opening 16 for the passage of a finger for the grip of the fire extinguisher.

The apparatus according to the present invention also contains a lever 7. The lever 7 is provided on either side with pins 8 serving as an axis of rotation. The action of the lever 7 makes it possible firstly to pressurize the extinguisher by perforation of the cartridge 20 during the extraction of the cap or safety cam 9, and then this same action allows the expulsion in one blow or intermittently the extinguishing agent 18. According to a particular embodiment, a groove is preformed on the upper surface of the lever 7 to allow the guide of the ramp 13 of the cam 9.

According to the present invention, the fire extinguisher valve head 1 comprises a security which caps it. The security called here cap or cam 9 is intended to protect any action on the lever 7; the seal 11, located on the front face 10 of the cam 9 is an integral part.

At the base of the two lateral faces 37 of the cam 9 is arranged longitudinally a rail 38 (see FIG. 3 and 4) provided for sliding, in the grooves of the valve body 3, of the cam 9 during the extraction of the -this.

In the center of the cam 9, inside the upper face 12, is located the sliding ramp 13 for tilting the lever 7 during the pulling of the safety cam 9.

On the rear part of the cam 9, opposite the outlet passage 6 of the extinguishing agent, is arranged an opening 14 allowing the passage of a finger provided for its extraction by sliding.

According to a preferred embodiment of the invention, the ergonomic shape of the cam allows a complete grip in order to allow a second possibility of extraction by sliding (trigger type colt).

The two lateral faces and the upper face may have an arrow indicating the direction of traction.

The sliding traction illustrated by the arrow 48 drives the cam or safety cap 9 outside the valve 1. During this operation, the cam 9 splits the seal 11 and the sliding ramp 13 tilts the lever 7: this action allows the realization of the pressurization of the fire extinguisher. This action, also called "prepercussion", is illustrated in Figures 2 to 4.

The tamperproof seal 11, which is an integral part of the cam or safety cap 9, is a control element that makes it possible to instantly visualize whether the extinguisher has been used or not. This element 11 can be removed or removed only part of rupture thereof. It is fractured during the extraction of the cam or safety cap 9 (Figure 2).

The rod or drawer 5 is the central element of the valve 1. The rod 5 consists of a body, three O-ring type seals, 29, 30, 31, and a return spring 28. The seal upper 29 seals the central channel 4 beyond the outlet channel 6 of the extinguishing agent. The central seal 30 seals in front of this outlet channel 6. The lower seal 31 seals the chamber containing the return spring 28. The action on the control lever 7 allows the movement of the rod 5 in the central channel 4. This displacement of the rod 5 releases the central seal 30 from its housing and allows the expulsion of the extinguishing agent 18 through the emptying channel 6. The return spring 28 allows the rod 5 to resume its initial position as soon as the action on the lever 7 is canceled.

The upper centralizer 22 is composed of a chamber and a retaining ring 27. The chamber of the upper centralizer is intended to receive the return spring 28 of the rod 5. The retaining ring 27 serves as support for this purpose. return spring 28, and centering of the rod 5 with respect to the central channel 4. This ring 27 comprises openings (or holes) 39 for the passage of the extinguishing agent 18.

According to a particular embodiment of the present invention, the lower or internal part of the apparatus comprises a bottle 17 having a cylindrical wall and a bottom 40 of curved shape. The bottle 17 comprises a tube 19 in which is placed a lower centralizer 23, a piston assembly 45 and the propellant cartridge 20 21. The upper portion 41 and the lower portion 42 of the tube 19 are connected by a transverse wall 56 provided with one or more openings 43 (two are shown in FIGS. 1-5). These elements are described below.

The central tube 19 is intended to lead the extinguishing agent 18 to the emptying channel 6. Equipped with its various components, it is threadedly connected to the valve body 3. Guide and retaining grooves are provided for the assembly and the maintenance of its different constituents. The central tube 19 is divided into an upper portion 41 and a lower portion 42 whose outer diameter is smaller than the outer diameter of the upper portion 41 of said tube 19.

In the upper portion 41 of the central tube 19 is a lower centralizer 23 which is composed of a cylindrical chamber 44 from which emerges (is profiled) one or more outlets 24 (two are shown in Figures 1 to 5) for directing the propellant 21. This or these outlets 24, called "ejector" or "diffuser" through the transverse wall 56 of the tube 19 at the openings 43, to expel the propellant gas 21 directly into the mass of the extinguishing agent 18.

Just below the openings 43 (pierced in the transverse wall 56 connecting the upper part 41 to the lower part 42 of the tube 19) and contiguous to the outer wall of the lower tube 42, is made one or more (in relation to the number of diffusers 24 of the lower centralizer 23) deflectors 26 creating one or more cells 25 in direct communication with the opening or openings 43. This or these deflectors 26 forming this or these cells 25, in which are housed or the diffusers 24 of said lower centralizer 23 , are profiled downwards in their inner parts at an angle of at least 30 ° to the horizontal. This or these deflectors 26 serve to direct the propellant gas 21 in the bottle 17 during the perforation of the cartridge 20 to this extent, thus enabling the extinguishing agent 18 contained in said bottle 17 to be effectively de-packed.

The lower centralizer 23 is composed of a circular wall and a transverse wall forming a cylindrical chamber 44 for receiving the piston assembly 45. The piston assembly is composed of a piston 45, an o-ring type seal 47, a holding spring 46, a striker 34, the assembly being mounted on the neck 32 of the cartridge 20 of propellant 21.

Referring to Figures 2, 3, 4, and 5 the operation of an apparatus according to the present invention is shown.

A first step, illustrated in Figure 2, is to extract (arrow 48) the safety cap or cam 9 out of the valve body 3 by firmly holding the device 2 and making a rapid and energetic traction on the safety 9, until complete extraction. This extraction, made by sliding perpendicularly to the fire extinguisher 2, automatically causes the rupture of the tamper-proof seal 11. During this operation, the safety cam 9, thanks to the sliding ramp 13, causes the lever 7 to tilt completely and then to release.

During its tilting illustrated by the arrow 49 in Figure 3, the control lever 7 pushes on the rod 5 by compressing the return spring 28. This step is illustrated in Figure 3. The rod 5 pushes the cartridge 20 which drives in its movement the piston 45 while compressing the retaining spring 46. The striker 34 being fixed, the tip thereof pierces the cartridge 20.

Under the effect of the perforation, the gas 21 contained in the cartridge 20 is violently expelled into the mass of the extinguishing agent 18 by the diffuser (s) 24.

Thanks to the return spring 28 of the rod 5, the emptying channel 6 is obstructed, and the control lever 7 resumes its activation position illustrated by the arrow 50. The release of the gas 21 contained in the cartridge 20 is expelled directly in the bottle containing the extinguishing agent 18 (FIG. 4). The expulsion is illustrated by the curves 51. The extinguisher 2 is pressurized and ready for use.

FIG. 5 then shows the extinguisher 2 being emptied. A manual push illustrated by the arrow 51 on the control lever 7 again causes the rod 5 to move and instantaneously allows the extinguishing agent 18 to be emptied, illustrated by the curves and arrows 52, 53 and 54. The return spring 28 resets the rod 5 in its initial position as soon as the thrust on the control lever 7 is released. The emptying channel 6 is thus again obstructed.

These last two operations can be performed as many times as necessary, until complete expulsion of the extinguishing agent contained in the bottle.

The description given above relates to a fire extinguisher and its activation in "two" shots. In said apparatus used in "two shots" the pressurization of the fire extinguisher is achieved by a first action on the control lever; this must be done automatically when you retrieve the security. A second action on the lever allows the extinguishing agent to be drained. The devices of the present invention are therefore made in accordance with the EN3 standard for the manufacture of fire extinguishers.

The present invention also relates to the use of a valve head according to the invention in a fire extinguisher apparatus. The present invention also relates to the use of a fire extinguisher apparatus, preferably of the auxiliary pressure type for extinguishing a fire. An apparatus according to the invention can for example be used in the automotive sector, the professional fire sector, or the domestic sector.

Claims (12)

Valve head (1) for fire extinguisher (2) characterized in that it comprises a valve body (3) comprising a central channel (4) for receiving a rod (5), and a lateral channel (6). constituting a drain channel of an extinguishing agent, a control lever (7) connected to said valve body (3) by pins (8), and a safety cam (9) removably and slidably mounted on top of the valve body (3), completely covering said control lever (7), said cam (9) being formed in one piece and having on a front face (10) a seal (11) forming an integral part of said piece and which can be torn off when the safety cam (9) is extracted, said safety cam (9) comprising an upper wall (12) provided at its center with a sliding ramp (13) located on the face lower of said upper wall (12) said sliding ramp (13) for tilting levie r (7) when pulling the safety cam (9). 2. Head according to claim 1, characterized in that the top of the valve body (3) is provided with longitudinal grooves located on either side of the control lever (7) grooves serving as a slide (55) to said safety cam (9). 3. Head according to claim 2, characterized in that the longitudinal parts of the base of the safety cam (9) are shaped in the form of rails provided for the sliding of the safety cam in the grooves of the valve body (3). ). 4. Head according to any one of claims 1 to 3, characterized in that the portion of the safety cam (9) opposite the exit passage of the extinguishing agent is provided with an opening (14) serving as taken to pull the safety cam (9). 5. Head according to any one of claims 1 to 4, characterized in that the valve body (3) comprises on the top of its front face (15) a housing adapted to receive the lower portion of the seal (11) of the safety cam (9). 6. Head according to any one of claims 1 to 5, characterized in that the valve body (3) comprises on the opposite portion to the drain channel (6) an opening (16) acting as a hold-down socket. extinguisher (2). 7. Head according to any one of claims 1 to 6, characterized in that the safety cam (9) comprises two side walls on either side of the upper wall, said side walls and upper having an arrow indicating the direction of traction. 8. Use / application of a valve head according to any one of claims 1 to 7 for an auxiliary pressure extinguisher. A fire extinguisher apparatus (2) comprising a fire extinguisher valve head (1) according to any one of claims 1 to 7. Apparatus according to claim 9, comprising: - a body (17) containing a extinguishing agent (18) of the fire-extinguishing powder type, and a central tube (19) provided inside said body (17), in which is placed a cartridge (20) under pressure containing a propellant (21). Apparatus according to claim 9 or 10, characterized in that said extinguisher valve head (1) comprises: a valve body (3) mainly comprising a central channel (4) for receiving a rod (5), and a side channel (6) constituting a drain channel of the extinguishing agent, a rod (5), mounted in said central channel (4) of the valve body (3), and controlling the opening and closing of said channel draining device (6), an upper centering device (22), for centering said rod (5) with respect to said drain channel (6), a control lever (7) connected to said valve body (3) by trunnions (8), and a safety cam (9) (safety cover, safety cover) removably and slidably mounted on top of the valve body (3), completely covering said control lever (7), said cam (9) being formed in one piece and having on one front face (10) a seal (11) integral with said it is capable of being torn off when the safety cam (9) is extracted, said safety cam (9) comprising an upper wall (12) provided at its center with a sliding ramp (13) located on the lower face of said upper wall (12) said sliding ramp (13) for tilting of the lever (7) during the pulling of the safety cam (9). 12. Fire extinguishing method using a fire extinguisher (2) according to any one of claims 9 to 11.